{"id":"CVE-2026-89761","title":"kernel: apparmor: fix out-of-bounds write when null terminating a label vec (CVE-2026-89761)","summary":"A flaw was found in the Linux kernel's AppArmor security module. An out-of-bounds write vulnerability exists when null terminating a label vector due to improper memory allocation. An unprivileged local attacker can exploit this by writing…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":"CWE-787","vendor":"Red Hat","product":"Linux","affected":["Linux >= f1bd904175e8190ce14aedee37e207ab51fe3b30 < 9124e078ea2250d8d01d2162a550acb01ef5bf48","Linux >= f1bd904175e8190ce14aedee37e207ab51fe3b30 < 28069434aef66b9d084f0609b7a29c171846815e","Linux >= f1bd904175e8190ce14aedee37e207ab51fe3b30 < 36bdd0b45ec3f4822832a56e9db8674c8450dfce","Linux >= f1bd904175e8190ce14aedee37e207ab51fe3b30 < 9f1e40193eef7f047e6b77cfb4b4cafdecd7a123","Linux 4.13"],"published":"2026-09-11","updated":"2026-09-21","sourceUpdated":"2026-09-21T18:29:12+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89761.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89761.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89761"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532235"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89761"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89761"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89761.mbox"},{"url":"https://git.kernel.org/stable/c/9124e078ea2250d8d01d2162a550acb01ef5bf48"},{"url":"https://git.kernel.org/stable/c/28069434aef66b9d084f0609b7a29c171846815e"},{"url":"https://git.kernel.org/stable/c/36bdd0b45ec3f4822832a56e9db8674c8450dfce"},{"url":"https://git.kernel.org/stable/c/9f1e40193eef7f047e6b77cfb4b4cafdecd7a123"}],"tags":["csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.0012,"epssPercentile":0.02063,"scores":{"vendor":5.5,"cna":7.8},"ingestedAt":"2026-09-14T15:23:07.472Z","slug":"CVE-2026-89761","body":"## Overview\n\nA flaw was found in the Linux kernel's AppArmor security module. An out-of-bounds write vulnerability exists when null terminating a label vector due to improper memory allocation. An unprivileged local attacker can exploit this by writing to specific system files, potentially leading to a denial of service (DoS) or, in some cases, privilege escalation. This vulnerability requires an AppArmor policy to be loaded on the system.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89761.json)\n\n**kernel: apparmor: fix out-of-bounds write when null terminating a label vec** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-21.\n\nNot affected:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 6\n- Red Hat Enterprise Linux 7\n- Red Hat Enterprise Linux 8\n- Red Hat Enterprise Linux 9\n- Red Hat OpenShift Container Platform 4\n\n## Remediation\n\nRefer to the advisory for fix availability.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":208936,"id":"CVE-2026-89761","ts":1790062294221,"field":"cvss","old":"7.8","new":"5.5"},{"seq":208935,"id":"CVE-2026-89761","ts":1790062294221,"field":"severity","old":"high","new":"medium"},{"seq":197664,"id":"CVE-2026-89761","ts":1789384318305,"field":"cvss","old":"6.5","new":"7.8"},{"seq":197663,"id":"CVE-2026-89761","ts":1789384318305,"field":"severity","old":"medium","new":"high"},{"seq":183845,"id":"CVE-2026-89761","ts":1789356677646,"field":"cvss","old":"7.8","new":"6.5"},{"seq":183844,"id":"CVE-2026-89761","ts":1789356677646,"field":"severity","old":"high","new":"medium"},{"seq":153648,"id":"CVE-2026-89761","ts":1789285351715,"field":"cvss","old":null,"new":"7.8"},{"seq":153647,"id":"CVE-2026-89761","ts":1789285351715,"field":"severity","old":"none","new":"high"},{"seq":147578,"id":"CVE-2026-89761","ts":1789270211459,"field":"cvss","old":null,"new":"6.5"},{"seq":147577,"id":"CVE-2026-89761","ts":1789270211459,"field":"severity","old":"none","new":"medium"},{"seq":109336,"id":"CVE-2026-89761","ts":1789183731476,"field":"cvss","old":null,"new":"6.5"},{"seq":109335,"id":"CVE-2026-89761","ts":1789183731476,"field":"severity","old":"none","new":"medium"}]}