{"id":"CVE-2026-89670","title":"kernel: nfsd: hold rcu across localio cmpxchg retry (CVE-2026-89670)","summary":"A flaw was found in the Linux kernel's Network File System Daemon (nfsd) component. A race condition exists in the `nfsd_open_local_fh()` function where an `nfsd_file` object can be freed and its memory recycled while another process attem…","severity":"medium","cvss":4.7,"cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":["CWE-416","CWE-825"],"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","affected":["enterprise_linux 10"],"published":"2026-09-11","updated":"2026-10-21","sourceUpdated":"2026-10-21T09:59:24+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89670.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89670.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89670"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532286"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89670"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89670"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89670.mbox"},{"url":"https://kernelcve.org/list/?q=CVE-2026-89670"},{"url":"https://git.kernel.org/stable/c/763c0bad872368304db718f79af7e93048885c67"},{"url":"https://git.kernel.org/stable/c/559570f91a7d4d199a72105e4980bef791f4cbf1"},{"url":"https://git.kernel.org/stable/c/58884694978a3d7d111edb433d7fd6a6c5af2f34"}],"tags":["csaf","vex","red-hat","cve.org"],"epss":0.00173,"epssPercentile":0.06733,"scores":{"vendor":7,"cna":7.8},"ingestedAt":"2026-09-14T15:23:07.473Z","slug":"CVE-2026-89670","body":"## Overview\n\nA flaw was found in the Linux kernel's Network File System Daemon (nfsd) component. A race condition exists in the `nfsd_open_local_fh()` function where an `nfsd_file` object can be freed and its memory recycled while another process attempts to access it. This can lead to a use-after-free vulnerability, allowing an attacker to potentially cause memory corruption, disclose sensitive information, or execute arbitrary code.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10 · no fix planned: Red Hat Enterprise Linux 10 · updated 2026-10-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89670.json)\n\n**kernel: nfsd: hold rcu across localio cmpxchg retry** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-10-21.\n\nAffected:\n\n- Red Hat Enterprise Linux 10\n\nNo fix planned:\n\n- Red Hat Enterprise Linux 10\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 Enterprise Linux 9\n- Red Hat OpenShift Container Platform 4\n\n## Remediation\n\nFix deferred\n\nWorkarounds / mitigations:\n\n- Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.","depth":"sunlit","depthScore":26,"depthScoreParts":{"impact":25.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":227001,"id":"CVE-2026-89670","ts":1792584975456,"field":"cvss","old":"7.8","new":"4.7"},{"seq":227000,"id":"CVE-2026-89670","ts":1792584975456,"field":"severity","old":"high","new":"medium"},{"seq":224634,"id":"CVE-2026-89670","ts":1792401446790,"field":"cvss","old":"7","new":"7.8"},{"seq":208075,"id":"CVE-2026-89670","ts":1789922704978,"field":"cvss","old":"7.5","new":"7"},{"seq":202987,"id":"CVE-2026-89670","ts":1789403733244,"field":"cvss","old":"7.8","new":"7.5"},{"seq":197773,"id":"CVE-2026-89670","ts":1789384318788,"field":"cvss","old":"7.5","new":"7.8"},{"seq":183692,"id":"CVE-2026-89670","ts":1789356676976,"field":"cvss","old":"7.8","new":"7.5"},{"seq":153534,"id":"CVE-2026-89670","ts":1789285351182,"field":"cvss","old":null,"new":"7.8"},{"seq":153533,"id":"CVE-2026-89670","ts":1789285351182,"field":"severity","old":"none","new":"high"},{"seq":147464,"id":"CVE-2026-89670","ts":1789270211011,"field":"cvss","old":null,"new":"7.5"},{"seq":147463,"id":"CVE-2026-89670","ts":1789270211011,"field":"severity","old":"none","new":"high"},{"seq":109216,"id":"CVE-2026-89670","ts":1789183730763,"field":"cvss","old":null,"new":"7.5"},{"seq":109215,"id":"CVE-2026-89670","ts":1789183730763,"field":"severity","old":"none","new":"high"}]}