{"id":"CVE-2026-89659","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during delegation revoke\n\nA delegation stateid holds only a bare pointer to its owning\nnfs4_client and does not keep it alive","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during delegation revoke\n\nA delegation stateid holds only a bare pointer to its owning\nnfs4_client and does not keep it alive.  The …","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-825"],"vendor":"Linux","product":"Linux","affected":["Linux >= 3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 < 0dd276b1324a5e08e83c6f675919946c9f0d61c9","Linux >= 3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 < 3c0a53ee0b442348d8d2286d6960d3f07bb3a3d3","Linux >= 3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 < 2a9d637c2a8fd8ac29ad9b29f28d122ef75c1a56","Linux >= 3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 < 4683ca76b3b7e5808338491c6eb3c20e6b4894d5","Linux 3.10"],"published":"2026-09-11","updated":"2026-09-21","sourceUpdated":"2026-09-21T14:17:24.513","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-89659","references":[{"url":"https://git.kernel.org/stable/c/0dd276b1324a5e08e83c6f675919946c9f0d61c9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2a9d637c2a8fd8ac29ad9b29f28d122ef75c1a56","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3c0a53ee0b442348d8d2286d6960d3f07bb3a3d3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4683ca76b3b7e5808338491c6eb3c20e6b4894d5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89659.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89659"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532119"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89659"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89659"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89659.mbox"}],"tags":["nvd","cve.org","csaf","vex","red-hat","score-dispute"],"epss":0.00435,"epssPercentile":0.37191,"scores":{"nvd":9.8,"cna":9.8,"vendor":7},"ingestedAt":"2026-09-14T15:23:07.473Z","slug":"CVE-2026-89659","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during delegation revoke\n\nA delegation stateid holds only a bare pointer to its owning\nnfs4_client and does not keep it alive.  The client survives its\nstateids only because __destroy_client() drains cl_delegations and\ncl_revoked before free_client() runs.\n\nnfs4_laundromat() breaks that invariant: it unhashes an\nexpired delegation from cl_delegations, drops deleg_lock, then\nrevoke_delegation() relinks it onto cl_revoked under cl_lock.  In that\nwindow the delegation is on neither list, so client_has_state() can\nreport no remaining state.\n\nEvery teardown path first requires cl_rpc_users to be zero, but\nthe laundromat holds no such reference.  A client whose recalled\ndelegation has just timed out can therefore reach free_client()\nwhile revoke_delegation() is still about to dereference cl_lock,\na use-after-free.\n\nPin the client with cl_rpc_users across the revoke so teardown blocks\nuntil it completes, then reap the delegation from cl_revoked.  A client\nalready expiring reaps its own, so skip it and leave the delegation on\ndel_recall_lru.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · 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, Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89659.json)","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":208377,"id":"CVE-2026-89659","ts":1789997913380,"field":"cvss","old":"7","new":"9.8"},{"seq":208376,"id":"CVE-2026-89659","ts":1789997913380,"field":"severity","old":"high","new":"critical"},{"seq":205541,"id":"CVE-2026-89659","ts":1789576724685,"field":"cvss","old":"6.4","new":"7"},{"seq":205540,"id":"CVE-2026-89659","ts":1789576724685,"field":"severity","old":"medium","new":"high"},{"seq":202997,"id":"CVE-2026-89659","ts":1789403733284,"field":"cvss","old":"9.8","new":"6.4"},{"seq":202996,"id":"CVE-2026-89659","ts":1789403733284,"field":"severity","old":"critical","new":"medium"},{"seq":197785,"id":"CVE-2026-89659","ts":1789384318843,"field":"cvss","old":"6.4","new":"9.8"},{"seq":197784,"id":"CVE-2026-89659","ts":1789384318843,"field":"severity","old":"medium","new":"critical"},{"seq":183777,"id":"CVE-2026-89659","ts":1789356677345,"field":"cvss","old":"9.8","new":"6.4"},{"seq":183776,"id":"CVE-2026-89659","ts":1789356677345,"field":"severity","old":"critical","new":"medium"},{"seq":153516,"id":"CVE-2026-89659","ts":1789285351110,"field":"cvss","old":null,"new":"9.8"},{"seq":153515,"id":"CVE-2026-89659","ts":1789285351110,"field":"severity","old":"none","new":"critical"},{"seq":147760,"id":"CVE-2026-89659","ts":1789270212184,"field":"cvss","old":null,"new":"6.4"},{"seq":147759,"id":"CVE-2026-89659","ts":1789270212184,"field":"severity","old":"none","new":"medium"},{"seq":109512,"id":"CVE-2026-89659","ts":1789183732230,"field":"cvss","old":null,"new":"6.4"},{"seq":109511,"id":"CVE-2026-89659","ts":1789183732230,"field":"severity","old":"none","new":"medium"}]}