{"id":"CVE-2026-89686","title":"kernel: nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke (CVE-2026-89686)","summary":"A flaw was found in the Linux kernel's Network File System Daemon (nfsd) for NFSv4 layouts. A race condition allows a remote attacker to trigger a kernel panic, leading to a Denial of Service (DoS). This occurs when the `nfsd4_alloc_layout…","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 7","enterprise_linux 8","enterprise_linux 9","openshift_container_platform 4"],"published":"2026-09-11","updated":"2026-09-21","sourceUpdated":"2026-09-21T11:41:19+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89686.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89686.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89686"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532098"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89686"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89686"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89686.mbox"},{"url":"https://git.kernel.org/stable/c/607a56fea772c1f4f4989d8e255dd4f7192d9604"},{"url":"https://git.kernel.org/stable/c/97bda8b4284d90897a1f1922e5082ff9e35d7c7e"},{"url":"https://git.kernel.org/stable/c/c517f27498757e616d2a8fe6d16caad1fee422e6"},{"url":"https://git.kernel.org/stable/c/ca94ba36172046be6a694a7986f6931e47ed4d51"}],"tags":["csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00671,"epssPercentile":0.50213,"scores":{"vendor":5.3,"cna":9.8},"ingestedAt":"2026-09-14T15:23:07.473Z","slug":"CVE-2026-89686","body":"## Overview\n\nA flaw was found in the Linux kernel's Network File System Daemon (nfsd) for NFSv4 layouts. A race condition allows a remote attacker to trigger a kernel panic, leading to a Denial of Service (DoS). This occurs when the `nfsd4_alloc_layout_stateid` function accesses a file pointer without proper locking during a concurrent delegation revoke, which can be orchestrated by two NFS clients interacting with the same file.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, 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 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89686.json)\n\n**kernel: nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-21.\n\nAffected:\n\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\nNo fix planned:\n\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\nNot affected:\n\n- Red Hat Enterprise Linux 6\n\n## Remediation\n\nAffected","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":38.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":208464,"id":"CVE-2026-89686","ts":1790005708211,"field":"cvss","old":"5.3","new":"7"},{"seq":208463,"id":"CVE-2026-89686","ts":1790005708211,"field":"severity","old":"medium","new":"high"},{"seq":202995,"id":"CVE-2026-89686","ts":1789403733276,"field":"cvss","old":"9.8","new":"5.3"},{"seq":202994,"id":"CVE-2026-89686","ts":1789403733276,"field":"severity","old":"critical","new":"medium"},{"seq":197740,"id":"CVE-2026-89686","ts":1789384318642,"field":"cvss","old":"5.3","new":"9.8"},{"seq":197739,"id":"CVE-2026-89686","ts":1789384318642,"field":"severity","old":"medium","new":"critical"},{"seq":183677,"id":"CVE-2026-89686","ts":1789356676907,"field":"cvss","old":"9.8","new":"5.3"},{"seq":183676,"id":"CVE-2026-89686","ts":1789356676907,"field":"severity","old":"critical","new":"medium"},{"seq":153562,"id":"CVE-2026-89686","ts":1789285351293,"field":"cvss","old":null,"new":"9.8"},{"seq":153561,"id":"CVE-2026-89686","ts":1789285351293,"field":"severity","old":"none","new":"critical"},{"seq":147754,"id":"CVE-2026-89686","ts":1789270212161,"field":"cvss","old":null,"new":"5.3"},{"seq":147753,"id":"CVE-2026-89686","ts":1789270212161,"field":"severity","old":"none","new":"medium"},{"seq":109510,"id":"CVE-2026-89686","ts":1789183732222,"field":"cvss","old":null,"new":"5.3"},{"seq":109509,"id":"CVE-2026-89686","ts":1789183732222,"field":"severity","old":"none","new":"medium"}]}