{"id":"CVE-2026-89662","title":"kernel: NFSD: Prevent lock owner use-after-free during client teardown (CVE-2026-89662)","summary":"A flaw was found in the Linux kernel's Network File System Daemon (NFSD). During client teardown, a race condition can occur where a lock owner is freed while still being referenced, leading to a use-after-free vulnerability. This can resu…","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-476","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","affected":["enterprise_linux 10","enterprise_linux 6","enterprise_linux 7","enterprise_linux 8","enterprise_linux 9","openshift_container_platform 4"],"published":"2026-09-11","updated":"2026-09-15","sourceUpdated":"2026-09-15T13:23:52+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89662.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89662.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89662"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532486"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89662"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89662"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89662.mbox"},{"url":"https://git.kernel.org/stable/c/42d7954b0a1907d4ef122aef94561952a033cdc3"},{"url":"https://git.kernel.org/stable/c/bb38ff8b4dafbbd1781ad37cd96722fdf2cd972a"},{"url":"https://git.kernel.org/stable/c/b8bad5a11416b26cc7fd4b18fba46d75ff636558"},{"url":"https://git.kernel.org/stable/c/1ce74d1b7770e69735e8f8e509807af4ff9c8ee7"},{"url":"https://git.kernel.org/stable/c/a6ead6fff3a7d03e49845f048f7000a2e0d34431"},{"url":"https://git.kernel.org/stable/c/4804c58f73a80d12df1de323bf97a164f6ee8743"},{"url":"https://git.kernel.org/stable/c/8cf4ff0a7c083dd5e0067f517d63979b74b66649"},{"url":"https://git.kernel.org/stable/c/5e2fa29d223a9a1e6a948e40b109d09081d1decd"}],"tags":["csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00684,"epssPercentile":0.50728,"scores":{"vendor":7,"cna":9.8},"ingestedAt":"2026-09-14T15:23:07.450Z","slug":"CVE-2026-89662","body":"## Overview\n\nA flaw was found in the Linux kernel's Network File System Daemon (NFSD). During client teardown, a race condition can occur where a lock owner is freed while still being referenced, leading to a use-after-free vulnerability. This can result in a NULL dereference, potentially causing a system crash and a denial of service.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89662.json)\n\n**kernel: NFSD: Prevent lock owner use-after-free during client teardown** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-15.\n\nAffected:\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\nNo fix planned:\n\n- Red Hat Enterprise Linux 6\n- Red Hat Enterprise Linux 10\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\nOut of support scope","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":38.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":203867,"id":"CVE-2026-89662","ts":1789490210416,"field":"cvss","old":"9.8","new":"7"},{"seq":203866,"id":"CVE-2026-89662","ts":1789490210416,"field":"severity","old":"critical","new":"high"},{"seq":197783,"id":"CVE-2026-89662","ts":1789384318834,"field":"cvss","old":"5.3","new":"9.8"},{"seq":197782,"id":"CVE-2026-89662","ts":1789384318834,"field":"severity","old":"medium","new":"critical"},{"seq":183707,"id":"CVE-2026-89662","ts":1789356677042,"field":"cvss","old":"9.8","new":"5.3"},{"seq":183706,"id":"CVE-2026-89662","ts":1789356677042,"field":"severity","old":"critical","new":"medium"},{"seq":153520,"id":"CVE-2026-89662","ts":1789285351126,"field":"cvss","old":null,"new":"9.8"},{"seq":153519,"id":"CVE-2026-89662","ts":1789285351126,"field":"severity","old":"none","new":"critical"},{"seq":147167,"id":"CVE-2026-89662","ts":1789270198309,"field":"cvss","old":null,"new":"5.3"},{"seq":147166,"id":"CVE-2026-89662","ts":1789270198309,"field":"severity","old":"none","new":"medium"},{"seq":108914,"id":"CVE-2026-89662","ts":1789183729520,"field":"cvss","old":null,"new":"5.3"},{"seq":108913,"id":"CVE-2026-89662","ts":1789183729520,"field":"severity","old":"none","new":"medium"}]}