{ "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-2026-34826", "tracking": { "current_release_date": "2026-04-03T15:35:51.691213Z", "generator": { "date": "2026-02-17T15:00:00Z", "engine": { "name": "V.E.L.M.A", "version": "1.7" } }, "id": "CVE-2026-34826", "initial_release_date": "2026-04-02T17:28:41.503252Z", "revision_history": [ { "date": "2026-04-02T17:28:41.503252Z", "number": "1", "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (1).| CWES updated (1)." }, { "date": "2026-04-02T17:28:43.691040Z", "number": "2", "summary": "NCSC Score created." }, { "date": "2026-04-02T17:38:54.578011Z", "number": "3", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (3).| References created (1).| CWES updated (1)." }, { "date": "2026-04-02T17:38:57.369527Z", "number": "4", "summary": "NCSC Score updated." }, { "date": "2026-04-02T20:12:01.608850Z", "number": "5", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (3).| CWES updated (1)." }, { "date": "2026-04-02T20:12:12.450083Z", "number": "6", "summary": "NCSC Score updated." }, { "date": "2026-04-03T00:44:14.466396Z", "number": "7", "summary": "Source created.| CVE status created. (valid)| Products connected (2)." }, { "date": "2026-04-03T00:44:18.158899Z", "number": "8", "summary": "NCSC Score updated." }, { "date": "2026-04-03T06:45:58.194655Z", "number": "9", "summary": "Description created for source." }, { "date": "2026-04-03T15:30:49.652234Z", "number": "10", "summary": "Source connected.| CVE status created. (valid)| EPSS created." }, { "date": "2026-04-03T15:30:52.548329Z", "number": "11", "summary": "NCSC Score updated." } ], "status": "interim", "version": "11" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/<2.2.23", "product": { "name": "vers:unknown/<2.2.23", "product_id": "CSAFPID-5985093" } }, { "category": "product_version_range", "name": "vers:unknown/>=3.0.0.beta1|<3.1.21", "product": { "name": "vers:unknown/>=3.0.0.beta1|<3.1.21", "product_id": "CSAFPID-5985094" } }, { "category": "product_version_range", "name": "vers:unknown/>=3.2.0|<3.2.6", "product": { "name": "vers:unknown/>=3.2.0|<3.2.6", "product_id": "CSAFPID-5985095" } } ], "category": "product_name", "name": "rack" } ], "category": "vendor", "name": "rack" }, { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:deb/unknown", "product": { "name": "vers:deb/unknown", "product_id": "CSAFPID-2065710" } } ], "category": "product_name", "name": "ruby-rack" } ], "category": "product_family", "name": "bookworm" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:deb/unknown", "product": { "name": "vers:deb/unknown", "product_id": "CSAFPID-2065711" } } ], "category": "product_name", "name": "ruby-rack" } ], "category": "product_family", "name": "bullseye" } ], "category": "vendor", "name": "Debian" } ] }, "vulnerabilities": [ { "cve": "CVE-2026-34826", "cwe": { "id": "CWE-770", "name": "Allocation of Resources Without Limits or Throttling" }, "notes": [ { "category": "description", "text": "Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.get_byte_ranges parses the HTTP Range header without limiting the number of individual byte ranges. Although the existing fix for CVE-2024-26141 rejects ranges whose total byte coverage exceeds the file size, it does not restrict the count of ranges. An attacker can supply many small overlapping ranges such as 0-0,0-0,0-0,... to trigger disproportionate CPU, memory, I/O, and bandwidth consumption per request. This results in a denial of service condition in Rack file-serving paths that process multipart byte range responses. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.", "title": "nvd - https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-34826" }, { "category": "description", "text": "Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.get_byte_ranges parses the HTTP Range header without limiting the number of individual byte ranges. Although the existing fix for CVE-2024-26141 rejects ranges whose total byte coverage exceeds the file size, it does not restrict the count of ranges. An attacker can supply many small overlapping ranges such as 0-0,0-0,0-0,... to trigger disproportionate CPU, memory, I/O, and bandwidth consumption per request. This results in a denial of service condition in Rack file-serving paths that process multipart byte range responses. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.", "title": "cveprojectv5 - https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/34xxx/CVE-2026-34826.json" }, { "category": "description", "text": "## Summary\n\n`Rack::Utils.get_byte_ranges` parses the HTTP `Range` header without limiting the number of individual byte ranges. Although the existing fix for CVE-2024-26141 rejects ranges whose total byte coverage exceeds the file size, it does not restrict the count of ranges. An attacker can supply many small overlapping ranges such as `0-0,0-0,0-0,...` to trigger disproportionate CPU, memory, I/O, and bandwidth consumption per request.\n\nThis results in a denial of service condition in Rack file-serving paths that process multipart byte range responses.\n\n## Details\n\n`Rack::Utils.get_byte_ranges` accepts a comma-separated list of byte ranges and validates them based on their aggregate size, but does not impose a limit on how many individual ranges may be supplied.\n\nAs a result, a request such as:\n\n```http\nRange: bytes=0-0,0-0,0-0,0-0,...\n```\n\ncan contain thousands of overlapping one-byte ranges while still satisfying the total-size check added for CVE-2024-26141.\n\nWhen such a header is processed by Rack’s file-serving code, each range causes additional work, including multipart response generation, per-range iteration, file seek and read operations, and temporary string allocation for response size calculation and output. This allows a relatively small request header to trigger disproportionately expensive processing and a much larger multipart response.\n\nThe issue is distinct from CVE-2024-26141. That fix prevents range sets whose total byte coverage exceeds the file size, but does not prevent a large number of overlapping ranges whose summed size remains within that limit.\n\n## Impact\n\nApplications that expose file-serving paths with byte range support may be vulnerable to denial of service.\n\nAn unauthenticated attacker can send crafted `Range` headers containing many small overlapping ranges to consume excessive CPU time, memory, file I/O, and bandwidth. Repeated requests may reduce application availability and increase pressure on workers and garbage collection.\n\n## Mitigation\n\n* Update to a patched version of Rack that limits the number of accepted byte ranges.\n* Reject or normalize multipart byte range requests containing excessive range counts.\n* Consider disabling multipart range support where it is not required.\n* Apply request filtering or header restrictions at the reverse proxy or application boundary to limit abusive `Range` headers.", "title": "github - https://api.github.com/advisories/GHSA-x8cg-fq8g-mxfx" }, { "category": "description", "text": "Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.get_byte_ranges parses the HTTP Range header without limiting the number of individual byte ranges. Although the existing fix for CVE-2024-26141 rejects ranges whose total byte coverage exceeds the file size, it does not restrict the count of ranges. An attacker can supply many small overlapping ranges such as 0-0,0-0,0-0,... to trigger disproportionate CPU, memory, I/O, and bandwidth consumption per request. This results in a denial of service condition in Rack file-serving paths that process multipart byte range responses. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.", "title": "debian - https://security-tracker.debian.org/tracker/CVE-2026-34826" }, { "category": "other", "text": "0.00039", "title": "EPSS" }, { "category": "other", "text": "4.1", "title": "NCSC Score" }, { "category": "other", "text": "Is related to (a version of) an uncommon product", "title": "NCSC Score top decreasing factors" } ], "product_status": { "known_affected": [ "CSAFPID-5985093", "CSAFPID-5985094", "CSAFPID-5985095", "CSAFPID-2065710", "CSAFPID-2065711" ] }, "references": [ { "category": "external", "summary": "Source - nvd", "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-34826" }, { "category": "external", "summary": "Source - cveprojectv5", "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/34xxx/CVE-2026-34826.json" }, { "category": "external", "summary": "Source - github", "url": "https://api.github.com/advisories/GHSA-x8cg-fq8g-mxfx" }, { "category": "external", "summary": "Source - debian", "url": "https://security-tracker.debian.org/tracker/CVE-2026-34826" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0" }, { "category": "external", "summary": "Reference - cveprojectv5; github; nvd", "url": "https://github.com/rack/rack/security/advisories/GHSA-x8cg-fq8g-mxfx" }, { "category": "external", "summary": "Reference - github", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34826" }, { "category": "external", "summary": "Reference - github", "url": "https://github.com/advisories/GHSA-x8cg-fq8g-mxfx" } ], "scores": [ { "cvss_v3": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "baseScore": 5.3, "baseSeverity": "MEDIUM" }, "products": [ "CSAFPID-2065710", "CSAFPID-2065711", "CSAFPID-5985093", "CSAFPID-5985094", "CSAFPID-5985095" ] } ], "title": "CVE-2026-34826" } ] }