{ "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-2026-27856", "tracking": { "current_release_date": "2026-03-31T14:41:34.053376Z", "generator": { "date": "2026-02-17T15:00:00Z", "engine": { "name": "V.E.L.M.A", "version": "1.7" } }, "id": "CVE-2026-27856", "initial_release_date": "2026-03-27T08:38:51.362288Z", "revision_history": [ { "date": "2026-03-27T08:38:51.362288Z", "number": "1", "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (1).| References created (1).| CWES updated (1)." }, { "date": "2026-03-27T08:38:56.228398Z", "number": "2", "summary": "NCSC Score created." }, { "date": "2026-03-27T09:25:04.993834Z", "number": "3", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (1).| CWES updated (1)." }, { "date": "2026-03-27T09:25:10.714271Z", "number": "4", "summary": "NCSC Score updated." }, { "date": "2026-03-27T11:11:02.567282Z", "number": "5", "summary": "Source connected.| CVE status created. (valid)| Products connected (2).| References created (3)." }, { "date": "2026-03-27T11:11:12.398279Z", "number": "6", "summary": "NCSC Score updated." }, { "date": "2026-03-27T11:34:50.360818Z", "number": "7", "summary": "NCSC Score updated." }, { "date": "2026-03-27T19:44:20.891553Z", "number": "8", "summary": "Unknown change." }, { "date": "2026-03-27T19:44:26.480086Z", "number": "9", "summary": "NCSC Score updated." }, { "date": "2026-03-27T21:06:33.854354Z", "number": "10", "summary": "Source connected.| CVE status created. (valid)| EPSS created." }, { "date": "2026-03-27T21:06:36.829707Z", "number": "11", "summary": "NCSC Score updated." }, { "date": "2026-03-28T07:41:30.603389Z", "number": "12", "summary": "Source created.| CVE status created. (valid)| Products connected (2)." }, { "date": "2026-03-28T07:41:32.268571Z", "number": "13", "summary": "NCSC Score updated." }, { "date": "2026-03-28T07:42:04.288265Z", "number": "14", "summary": "Description created for source." }, { "date": "2026-03-30T12:32:47.654461Z", "number": "15", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (10).| Product Identifiers created (5).| References created (3).| CWES updated (1).| Vendor_assessment created." }, { "date": "2026-03-30T12:32:51.318644Z", "number": "16", "summary": "NCSC Score updated." }, { "date": "2026-03-31T11:09:45.495804Z", "number": "17", "summary": "Products connected (1).| References created (1)." }, { "date": "2026-03-31T11:09:51.279295Z", "number": "18", "summary": "NCSC Score updated." } ], "status": "interim", "version": "18" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/<2.4.0", "product": { "name": "vers:unknown/<2.4.0", "product_id": "CSAFPID-5937944" } }, { "category": "product_version_range", "name": "vers:unknown/<2.4.3", "product": { "name": "vers:unknown/<2.4.3", "product_id": "CSAFPID-5937945" } } ], "category": "product_name", "name": "Dovecot" } ], "category": "vendor", "name": "Open Source" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:semver/<=2.3.0", "product": { "name": "vers:semver/<=2.3.0", "product_id": "CSAFPID-5924462" } } ], "category": "product_name", "name": "OX Dovecot Pro" } ], "category": "vendor", "name": "Open-Xchange GmbH" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:rpm/10", "product": { "name": "vers:rpm/10", "product_id": "CSAFPID-2858634", "product_identification_helper": { "cpe": "cpe:/o:redhat:enterprise_linux:10" } } } ], "category": "product_name", "name": "Red Hat Enterprise Linux 10" }, { "branches": [ { "category": "product_version_range", "name": "vers:rpm/6", "product": { "name": "vers:rpm/6", "product_id": "CSAFPID-1439321", "product_identification_helper": { "cpe": "cpe:/o:redhat:enterprise_linux:6" } } } ], "category": "product_name", "name": "Red Hat Enterprise Linux 6" }, { "branches": [ { "category": "product_version_range", "name": "vers:rpm/7", "product": { "name": "vers:rpm/7", "product_id": "CSAFPID-1439315", "product_identification_helper": { "cpe": "cpe:/o:redhat:enterprise_linux:7" } } } ], "category": "product_name", "name": "Red Hat Enterprise Linux 7" }, { "branches": [ { "category": "product_version_range", "name": "vers:rpm/8", "product": { "name": "vers:rpm/8", "product_id": "CSAFPID-1439317", "product_identification_helper": { "cpe": "cpe:/o:redhat:enterprise_linux:8" } } } ], "category": "product_name", "name": "Red Hat Enterprise Linux 8" }, { "branches": [ { "category": "product_version_range", "name": "vers:rpm/9", "product": { "name": "vers:rpm/9", "product_id": "CSAFPID-1439319", "product_identification_helper": { "cpe": "cpe:/o:redhat:enterprise_linux:9" } } } ], "category": "product_name", "name": "Red Hat Enterprise Linux 9" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:rpm/unknown", "product": { "name": "vers:rpm/unknown", "product_id": "CSAFPID-5958201" } } ], "category": "product_name", "name": "dovecot" } ], "category": "product_family", "name": "Red Hat Enterprise Linux 10" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:rpm/unknown", "product": { "name": "vers:rpm/unknown", "product_id": "CSAFPID-5958202" } } ], "category": "product_name", "name": "dovecot" } ], "category": "product_family", "name": "Red Hat Enterprise Linux 6" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:rpm/unknown", "product": { "name": "vers:rpm/unknown", "product_id": "CSAFPID-5958203" } } ], "category": "product_name", "name": "dovecot" } ], "category": "product_family", "name": "Red Hat Enterprise Linux 7" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:rpm/unknown", "product": { "name": "vers:rpm/unknown", "product_id": "CSAFPID-5958204" } } ], "category": "product_name", "name": "dovecot" } ], "category": "product_family", "name": "Red Hat Enterprise Linux 8" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:rpm/unknown", "product": { "name": "vers:rpm/unknown", "product_id": "CSAFPID-5958205" } } ], "category": "product_name", "name": "dovecot" } ], "category": "product_family", "name": "Red Hat Enterprise Linux 9" } ], "category": "vendor", "name": "Red Hat" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/unknown", "product": { "name": "vers:unknown/unknown", "product_id": "CSAFPID-1317176", "product_identification_helper": { "cpe": "cpe:/o:suse:opensuse:-" } } } ], "category": "product_name", "name": "SUSE openSUSE" } ], "category": "vendor", "name": "SUSE" }, { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:deb/unknown", "product": { "name": "vers:deb/unknown", "product_id": "CSAFPID-1411598" } } ], "category": "product_name", "name": "dovecot" } ], "category": "product_family", "name": "bookworm" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:deb/unknown", "product": { "name": "vers:deb/unknown", "product_id": "CSAFPID-1411534" } } ], "category": "product_name", "name": "dovecot" } ], "category": "product_family", "name": "bullseye" } ], "category": "vendor", "name": "Debian" } ] }, "vulnerabilities": [ { "cve": "CVE-2026-27856", "cwe": { "id": "CWE-208", "name": "Observable Timing Discrepancy" }, "notes": [ { "category": "description", "text": "Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attack. An attacker can use this to determine the configured credentials. Figuring out the credential will lead into full access to the affected component. Limit access to the doveadm http service port, install fixed version. No publicly available exploits are known.", "title": "cveprojectv5 - https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/27xxx/CVE-2026-27856.json" }, { "category": "description", "text": "Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attack. An attacker can use this to determine the configured credentials. Figuring out the credential will lead into full access to the affected component. Limit access to the doveadm http service port, install fixed version. No publicly available exploits are known.", "title": "nvd - https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-27856" }, { "category": "description", "text": "Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attack. An attacker can use this to determine the configured credentials. Figuring out the credential will lead into full access to the affected component. Limit access to the doveadm http service port, install fixed version. No publicly available exploits are known.", "title": "debian - https://security-tracker.debian.org/tracker/CVE-2026-27856" }, { "category": "description", "text": "A flaw was found in Doveadm, a component of Dovecot. An attacker can exploit a timing oracle vulnerability during the direct comparison of credentials. This allows the attacker to determine the configured credentials, potentially leading to full unauthorized access to the affected component.", "title": "redhat - https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-27856.json" }, { "category": "other", "text": "0.0003", "title": "EPSS" }, { "category": "other", "text": "3.8", "title": "NCSC Score" }, { "category": "other", "text": "There is product data available from source Certbundde, Is related to a product by vendor Suse", "title": "NCSC Score top increasing factors" }, { "category": "other", "text": "Is related to CWE-208 (Observable Timing Discrepancy), Is related to (a version of) an uncommon product, Is related to an uncommon product vendor, There is product data available from source Debian", "title": "NCSC Score top decreasing factors" }, { "category": "details", "text": "Severity: 3\n", "title": "Vendor assessment" } ], "product_status": { "known_affected": [ "CSAFPID-5924462", "CSAFPID-5937944", "CSAFPID-5937945", "CSAFPID-1411534", "CSAFPID-1411598", "CSAFPID-1439315", "CSAFPID-1439321", "CSAFPID-5958202", "CSAFPID-5958203", "CSAFPID-1317176" ], "known_not_affected": [ "CSAFPID-1439317", "CSAFPID-1439319", "CSAFPID-2858634", "CSAFPID-5958201", "CSAFPID-5958204", "CSAFPID-5958205" ] }, "references": [ { "category": "external", "summary": "Source - cveprojectv5", "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/27xxx/CVE-2026-27856.json" }, { "category": "external", "summary": "Source - nvd", "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-27856" }, { "category": "external", "summary": "Source - certbundde", "url": "https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-0891.json" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0" }, { "category": "external", "summary": "Source - debian", "url": "https://security-tracker.debian.org/tracker/CVE-2026-27856" }, { "category": "external", "summary": "Source - redhat", "url": "https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-27856.json" }, { "category": "external", "summary": "Reference - cveprojectv5; nvd; redhat", "url": "https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json" }, { "category": "external", "summary": "Reference - certbundde", "url": "https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-0891.json" }, { "category": "external", "summary": "Reference - certbundde", "url": "https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2026-0891" }, { "category": "external", "summary": "Reference - certbundde", "url": "https://dovecot.org/mailman3/archives/list/dovecot@dovecot.org/thread/I4KFFV4IKP6M5MS67SWYHKDSDMSNILQG/" }, { "category": "external", "summary": "Reference - redhat", "url": "https://www.cve.org/CVERecord?id=CVE-2026-27856" }, { "category": "external", "summary": "Reference - redhat", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27856" }, { "category": "external", "summary": "Reference - certbundde", "url": "https://lists.opensuse.org/archives/list/security-announce@lists.opensuse.org/thread/OBSVSMBRLSXDJ3TFA22MX7UVQIY2WIIN/" } ], "scores": [ { "cvss_v3": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "baseScore": 7.4, "baseSeverity": "HIGH" }, "products": [ "CSAFPID-1317176", "CSAFPID-1411534", "CSAFPID-1411598", "CSAFPID-1439315", "CSAFPID-1439321", "CSAFPID-5924462", "CSAFPID-5937944", "CSAFPID-5937945", "CSAFPID-5958202", "CSAFPID-5958203" ] } ], "title": "CVE-2026-27856" } ] }