{"id":"CVE-2026-89695","title":"kernel: nfsd: cap decoded POSIX ACL count to bound sort cost (CVE-2026-89695)","summary":"A flaw was found in the Linux kernel's Network File System Daemon (nfsd). The `nfsd4_decode_posixacl()` function, responsible for decoding POSIX Access Control Lists (ACLs), does not properly cap the entry count received from a client. A r…","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-606","vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","affected":["openshift_container_platform 4"],"published":"2026-09-11","updated":"2026-09-16","sourceUpdated":"2026-09-16T12:25:18+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89695.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89695.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89695"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532373"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89695"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89695"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89695.mbox"},{"url":"https://git.kernel.org/stable/c/4bc1108e876153a2dd6d874052b99182c3603135"},{"url":"https://git.kernel.org/stable/c/ea14d71d6ecb925673761bcf79f781f7dc9042cc"}],"tags":["csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00488,"epssPercentile":0.40944,"scores":{"vendor":5.3,"cna":7.5},"ingestedAt":"2026-09-14T15:23:07.472Z","slug":"CVE-2026-89695","body":"## Overview\n\nA flaw was found in the Linux kernel's Network File System Daemon (nfsd). The `nfsd4_decode_posixacl()` function, responsible for decoding POSIX Access Control Lists (ACLs), does not properly cap the entry count received from a client. A remote attacker can exploit this by sending a specially crafted ACL with an excessively large entry count, leading to unbounded CPU usage during an O(n^2) sorting operation. This can result in a Denial of Service (DoS) for the affected server.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat OpenShift Container Platform 4 · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89695.json)\n\n**kernel: nfsd: cap decoded POSIX ACL count to bound sort cost** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-16.\n\nAffected:\n\n- Red Hat OpenShift Container Platform 4\n\nNo fix planned:\n\n- Red Hat OpenShift Container Platform 4\n\n## Remediation\n\nFix deferred","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":38.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":205447,"id":"CVE-2026-89695","ts":1789576718000,"field":"cvss","old":"5.3","new":"7"},{"seq":205446,"id":"CVE-2026-89695","ts":1789576718000,"field":"severity","old":"medium","new":"high"},{"seq":202816,"id":"CVE-2026-89695","ts":1789403731643,"field":"cvss","old":"7.5","new":"5.3"},{"seq":202815,"id":"CVE-2026-89695","ts":1789403731643,"field":"severity","old":"high","new":"medium"},{"seq":197730,"id":"CVE-2026-89695","ts":1789384318592,"field":"cvss","old":"5.3","new":"7.5"},{"seq":197729,"id":"CVE-2026-89695","ts":1789384318592,"field":"severity","old":"medium","new":"high"},{"seq":183345,"id":"CVE-2026-89695","ts":1789356674972,"field":"cvss","old":"7.5","new":"5.3"},{"seq":183344,"id":"CVE-2026-89695","ts":1789356674972,"field":"severity","old":"high","new":"medium"},{"seq":153576,"id":"CVE-2026-89695","ts":1789285351348,"field":"cvss","old":null,"new":"7.5"},{"seq":153575,"id":"CVE-2026-89695","ts":1789285351348,"field":"severity","old":"none","new":"high"},{"seq":147309,"id":"CVE-2026-89695","ts":1789270208767,"field":"cvss","old":null,"new":"5.3"},{"seq":147308,"id":"CVE-2026-89695","ts":1789270208767,"field":"severity","old":"none","new":"medium"},{"seq":109062,"id":"CVE-2026-89695","ts":1789183730160,"field":"cvss","old":null,"new":"5.3"},{"seq":109061,"id":"CVE-2026-89695","ts":1789183730160,"field":"severity","old":"none","new":"medium"}]}