{"id":"CVE-2026-89651","title":"kernel: ceph: bound MDSCapAuth path and fs_name decode in handle_session() (CVE-2026-89651)","summary":"A flaw was found in the Linux kernel's Ceph client. An out-of-bounds read vulnerability exists in the `handle_session()` function when decoding `MDSCapAuth` records. A malicious or compromised Metadata Server (MDS) can trigger this during …","severity":"high","cvss":7,"cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"vendor","cwe":"CWE-125","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","affected":["enterprise_linux 10","enterprise_linux 9"],"published":"2026-09-11","updated":"2026-09-18","sourceUpdated":"2026-09-18T20:12:22+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89651.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89651.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89651"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532282"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89651"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89651"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89651.mbox"},{"url":"https://git.kernel.org/stable/c/5f892c767b30e4fb0c744c59f9235c717383d2cd"},{"url":"https://git.kernel.org/stable/c/77933e22adfe813be2bd10be08d6e950103c3967"},{"url":"https://git.kernel.org/stable/c/c37db86d2b5e9b57001ccae7e7a727e95a4f9c02"},{"url":"https://git.kernel.org/stable/c/dc5c7dffda92ef372fa587c444a1c537373df824"}],"tags":["csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00626,"epssPercentile":0.48642,"scores":{"vendor":5.9,"cna":9.8},"ingestedAt":"2026-09-14T15:23:07.473Z","slug":"CVE-2026-89651","body":"## Overview\n\nA flaw was found in the Linux kernel's Ceph client. An out-of-bounds read vulnerability exists in the `handle_session()` function when decoding `MDSCapAuth` records. A malicious or compromised Metadata Server (MDS) can trigger this during session setup without client-side user interaction. This can force the kernel client to read past the message buffer, leading to a client crash and a Denial of Service (DoS).\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89651.json)\n\n**kernel: ceph: bound MDSCapAuth path and fs_name decode in handle_session()** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-18.\n\nAffected:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 9\n\nNo fix planned:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 9\n\nNot affected:\n\n- Red Hat Enterprise Linux 6\n- Red Hat Enterprise Linux 7\n- Red Hat Enterprise Linux 8\n- Red Hat OpenShift Container Platform 4\n\n## Remediation\n\nAffected","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":38.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":208120,"id":"CVE-2026-89651","ts":1789922716655,"field":"cvss","old":"5.9","new":"7"},{"seq":208119,"id":"CVE-2026-89651","ts":1789922716655,"field":"severity","old":"medium","new":"high"},{"seq":203001,"id":"CVE-2026-89651","ts":1789403733300,"field":"cvss","old":"9.8","new":"5.9"},{"seq":203000,"id":"CVE-2026-89651","ts":1789403733300,"field":"severity","old":"critical","new":"medium"},{"seq":197801,"id":"CVE-2026-89651","ts":1789384318916,"field":"cvss","old":"5.9","new":"9.8"},{"seq":197800,"id":"CVE-2026-89651","ts":1789384318916,"field":"severity","old":"medium","new":"critical"},{"seq":183715,"id":"CVE-2026-89651","ts":1789356677076,"field":"cvss","old":"9.8","new":"5.9"},{"seq":183714,"id":"CVE-2026-89651","ts":1789356677076,"field":"severity","old":"critical","new":"medium"},{"seq":153500,"id":"CVE-2026-89651","ts":1789285350814,"field":"cvss","old":null,"new":"9.8"},{"seq":153499,"id":"CVE-2026-89651","ts":1789285350814,"field":"severity","old":"none","new":"critical"},{"seq":147462,"id":"CVE-2026-89651","ts":1789270211003,"field":"cvss","old":null,"new":"5.9"},{"seq":147461,"id":"CVE-2026-89651","ts":1789270211003,"field":"severity","old":"none","new":"medium"},{"seq":109218,"id":"CVE-2026-89651","ts":1789183730771,"field":"cvss","old":null,"new":"5.9"},{"seq":109217,"id":"CVE-2026-89651","ts":1789183730771,"field":"severity","old":"none","new":"medium"}]}