{"id":"CVE-2026-89696","title":"kernel: nfsd: block non-SAVEFH ops after FOREIGN PUTFH to prevent NULL deref (CVE-2026-89696)","summary":"A flaw was found in the Linux kernel's Network File System (NFS) daemon (nfsd). A remote client can exploit this by sending a specially crafted NFS COMPOUND request. This request, when processed, can lead to a NULL pointer dereference in t…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":"CWE-476","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":"2026-09-21T11:52:00+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89696.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89696.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89696"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532408"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89696"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89696"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89696.mbox"},{"url":"https://git.kernel.org/stable/c/ffdc844e673d2bcb2af8c8c3eef8cdea59d0bf32"},{"url":"https://git.kernel.org/stable/c/00c84f4eec715e501efc080a5670114189e42507"},{"url":"https://git.kernel.org/stable/c/2d9846fd1c767920fddd4bde30eb35cd2969df13"},{"url":"https://git.kernel.org/stable/c/977e6f006a7a3ffc4216ae6034f768f8de6fd138"},{"url":"https://git.kernel.org/stable/c/35f248bd40b47b229d4999581df45b97daadd977"},{"url":"https://git.kernel.org/stable/c/311f7d926630940650447cbd1c932b076b40a6c4"},{"url":"https://git.kernel.org/stable/c/bf4d338dc8625d70c7f2cb0657d66851a7ac9154"},{"url":"https://git.kernel.org/stable/c/c59738a00aa51b16adc1b5ceb7c80877168efb4d"}],"tags":["csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00762,"epssPercentile":0.53406,"scores":{"vendor":5.5,"cna":7.5},"ingestedAt":"2026-09-14T15:23:07.449Z","slug":"CVE-2026-89696","body":"## Overview\n\nA flaw was found in the Linux kernel's Network File System (NFS) daemon (nfsd). A remote client can exploit this by sending a specially crafted NFS COMPOUND request. This request, when processed, can lead to a NULL pointer dereference in the nfsd kthread, causing the system to crash and resulting in a Denial of Service (DoS).\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-2026-89696.json)\n\n**kernel: nfsd: block non-SAVEFH ops after FOREIGN PUTFH to prevent NULL deref** — 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":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0.2,"exploitation":0,"ransomware":0},"changes":[{"seq":208460,"id":"CVE-2026-89696","ts":1790005707150,"field":"cvss","old":"7.5","new":"5.5"},{"seq":208459,"id":"CVE-2026-89696","ts":1790005707150,"field":"severity","old":"high","new":"medium"},{"seq":197728,"id":"CVE-2026-89696","ts":1789384318583,"field":"cvss","old":"5.9","new":"7.5"},{"seq":197727,"id":"CVE-2026-89696","ts":1789384318583,"field":"severity","old":"medium","new":"high"},{"seq":183702,"id":"CVE-2026-89696","ts":1789356677018,"field":"cvss","old":"7.5","new":"5.9"},{"seq":183701,"id":"CVE-2026-89696","ts":1789356677018,"field":"severity","old":"high","new":"medium"},{"seq":153578,"id":"CVE-2026-89696","ts":1789285351356,"field":"cvss","old":null,"new":"7.5"},{"seq":153577,"id":"CVE-2026-89696","ts":1789285351356,"field":"severity","old":"none","new":"high"},{"seq":147251,"id":"CVE-2026-89696","ts":1789270204499,"field":"cvss","old":null,"new":"5.9"},{"seq":147250,"id":"CVE-2026-89696","ts":1789270204499,"field":"severity","old":"none","new":"medium"},{"seq":109000,"id":"CVE-2026-89696","ts":1789183729901,"field":"cvss","old":null,"new":"5.9"},{"seq":108999,"id":"CVE-2026-89696","ts":1789183729901,"field":"severity","old":"none","new":"medium"}]}