{"id":"CVE-2026-89663","title":"kernel: nfsd: revoke copy-notify stateids before dropping their reference (CVE-2026-89663)","summary":"A flaw was found in the Linux kernel's Network File System Daemon (nfsd). This vulnerability arises from improper handling of \"copy-notify stateids\" during their revocation. When a stateid's reference is dropped without unlinking it, the m…","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-825","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","affected":["enterprise_linux 10","enterprise_linux 9","openshift_container_platform 4"],"published":"2026-09-11","updated":"2026-09-18","sourceUpdated":"2026-09-18T20:10:36+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89663.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89663.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89663"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532231"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89663"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89663"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89663.mbox"},{"url":"https://git.kernel.org/stable/c/5f00e0ab4de45d4f9e4bd0883cf2517acf63fc0d"},{"url":"https://git.kernel.org/stable/c/06a62f6dbc60791f4229c6950b1eec6b18df9af1"},{"url":"https://git.kernel.org/stable/c/a1fca0f7bbb7b100a39c7ba8dd7922c87c4237a3"},{"url":"https://git.kernel.org/stable/c/caddbeffab1eaba1d2bcf5ceda35547863466705"},{"url":"https://git.kernel.org/stable/c/6b8149448cdcb476fba4559d1ecc247efee9971b"},{"url":"https://git.kernel.org/stable/c/b56d2c5f01cddbeca7d11cce81d97db4ec9a464f"},{"url":"https://git.kernel.org/stable/c/ff8a3cff02b92b2a82f1a9876038fcf953ae9c25"},{"url":"https://git.kernel.org/stable/c/3b0c3595db99bb4bebd7c8aa8a36f3c50e411bb7"}],"tags":["csaf","vex","red-hat","cve.org"],"epss":0.00455,"epssPercentile":0.38692,"scores":{"vendor":7,"cna":8.8},"ingestedAt":"2026-09-14T15:23:07.450Z","slug":"CVE-2026-89663","body":"## Overview\n\nA flaw was found in the Linux kernel's Network File System Daemon (nfsd). This vulnerability arises from improper handling of \"copy-notify stateids\" during their revocation. When a stateid's reference is dropped without unlinking it, the memory can be freed while still in use by a reader, leading to a use-after-free condition. This can cause system instability and potentially allow for unauthorized access.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89663.json)\n\n**kernel: nfsd: revoke copy-notify stateids before dropping their reference** — rated Important 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- Red Hat OpenShift Container Platform 4\n\nNo fix planned:\n\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 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":208121,"id":"CVE-2026-89663","ts":1789922717174,"field":"cvss","old":"8.8","new":"7"},{"seq":197777,"id":"CVE-2026-89663","ts":1789384318806,"field":"cvss","old":"6.4","new":"8.8"},{"seq":197776,"id":"CVE-2026-89663","ts":1789384318806,"field":"severity","old":"medium","new":"high"},{"seq":183700,"id":"CVE-2026-89663","ts":1789356677009,"field":"cvss","old":"8.8","new":"6.4"},{"seq":183699,"id":"CVE-2026-89663","ts":1789356677009,"field":"severity","old":"high","new":"medium"},{"seq":153522,"id":"CVE-2026-89663","ts":1789285351134,"field":"cvss","old":null,"new":"8.8"},{"seq":153521,"id":"CVE-2026-89663","ts":1789285351134,"field":"severity","old":"none","new":"high"},{"seq":147584,"id":"CVE-2026-89663","ts":1789270211483,"field":"cvss","old":null,"new":"6.4"},{"seq":147583,"id":"CVE-2026-89663","ts":1789270211483,"field":"severity","old":"none","new":"medium"},{"seq":109340,"id":"CVE-2026-89663","ts":1789183731501,"field":"cvss","old":null,"new":"6.4"},{"seq":109339,"id":"CVE-2026-89663","ts":1789183731501,"field":"severity","old":"none","new":"medium"}]}