{"id":"CVE-2026-89691","title":"kernel: nfsd: clear opcnt on compound arg release to prevent OOB read (CVE-2026-89691)","summary":"A flaw was found in the Linux kernel's Network File System Daemon (nfsd) component. The nfsd4_release_compoundargs() function does not properly clear an internal counter (opcnt) when releasing a buffer. This oversight can lead to an out-of…","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 6","enterprise_linux 9","openshift_container_platform 4"],"published":"2026-09-11","updated":"2026-09-21","sourceUpdated":"2026-09-21T11:44:27+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89691.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89691.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89691"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532399"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89691"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89691"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89691.mbox"},{"url":"https://git.kernel.org/stable/c/58bcdfb2b2e412088839ae740b1a95154dc0b8d0"},{"url":"https://git.kernel.org/stable/c/ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a"},{"url":"https://git.kernel.org/stable/c/c1a4f7b1848f95302df598217e1c7a1410c2d0c5"},{"url":"https://git.kernel.org/stable/c/e879148867bd4c4cac42e063ffaffa187dddc6fe"}],"tags":["csaf","vex","red-hat","cve.org"],"epss":0.00125,"epssPercentile":0.02538,"scores":{"vendor":7.4,"cna":7.1},"ingestedAt":"2026-09-14T15:23:07.473Z","slug":"CVE-2026-89691","body":"## Overview\n\nA flaw was found in the Linux kernel's Network File System Daemon (nfsd) component. The nfsd4_release_compoundargs() function does not properly clear an internal counter (opcnt) when releasing a buffer. This oversight can lead to an out-of-bounds read, allowing an attacker to access adjacent memory and potentially leak sensitive information to userspace through netlink.\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 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89691.json)\n\n**kernel: nfsd: clear opcnt on compound arg release to prevent OOB read** — 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 6\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 9\n- Red Hat OpenShift Container Platform 4\n\nNot affected:\n\n- Red Hat Enterprise Linux 7\n- Red Hat Enterprise Linux 8\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,"exploitation":0,"ransomware":0},"changes":[{"seq":208461,"id":"CVE-2026-89691","ts":1790005707669,"field":"cvss","old":"7.4","new":"7"},{"seq":202975,"id":"CVE-2026-89691","ts":1789403733187,"field":"cvss","old":"7.1","new":"7.4"},{"seq":197734,"id":"CVE-2026-89691","ts":1789384318617,"field":"cvss","old":"7.4","new":"7.1"},{"seq":183668,"id":"CVE-2026-89691","ts":1789356676863,"field":"cvss","old":"7.1","new":"7.4"},{"seq":153572,"id":"CVE-2026-89691","ts":1789285351332,"field":"cvss","old":null,"new":"7.1"},{"seq":153571,"id":"CVE-2026-89691","ts":1789285351332,"field":"severity","old":"none","new":"high"},{"seq":147285,"id":"CVE-2026-89691","ts":1789270207005,"field":"cvss","old":null,"new":"7.4"},{"seq":147284,"id":"CVE-2026-89691","ts":1789270207005,"field":"severity","old":"none","new":"high"},{"seq":109040,"id":"CVE-2026-89691","ts":1789183730070,"field":"cvss","old":null,"new":"7.4"},{"seq":109039,"id":"CVE-2026-89691","ts":1789183730070,"field":"severity","old":"none","new":"high"}]}