{"id":"CVE-2026-89537","title":"kernel: SUNRPC: Reject short RFC 4121 MIC tokens in gss_krb5_verify_mic_v2 (CVE-2026-89537)","summary":"A flaw was found in the Linux kernel's SUNRPC implementation, specifically within the `gss_krb5_verify_mic_v2` function. A remote malicious Network File System (NFS) server could provide a specially crafted, short Kerberos Message Integrit…","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-125","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","affected":["enterprise_linux 10","enterprise_linux 6","enterprise_linux 7","enterprise_linux 8","enterprise_linux 9","openshift_container_platform 4"],"published":"2026-09-11","updated":"2026-09-18","sourceUpdated":"2026-09-18T21:56:01+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89537.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89537.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89537"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532109"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89537"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89537"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89537.mbox"},{"url":"https://git.kernel.org/stable/c/7a946b2e7207f968902f2147ab9b30726f82f7ab"},{"url":"https://git.kernel.org/stable/c/b94f6719dcd9f7a609bc5f459f85795900e77d25"}],"tags":["csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00516,"epssPercentile":0.42903,"scores":{"vendor":6.4,"cna":9.1},"ingestedAt":"2026-09-14T15:23:07.474Z","slug":"CVE-2026-89537","body":"## Overview\n\nA flaw was found in the Linux kernel's SUNRPC implementation, specifically within the `gss_krb5_verify_mic_v2` function. A remote malicious Network File System (NFS) server could provide a specially crafted, short Kerberos Message Integrity Code (MIC) token. This could lead to the kernel reading past an allocated memory buffer, potentially causing a denial of service or information disclosure.\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 7, Red Hat Enterprise Linux 8, 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 7, Red Hat Enterprise Linux 8, … · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89537.json)\n\n**kernel: SUNRPC: Reject short RFC 4121 MIC tokens in gss_krb5_verify_mic_v2** — rated Moderate 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 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\nNo fix planned:\n\n- Red Hat Enterprise Linux 6\n- Red Hat Enterprise Linux 10\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\nOut of support scope","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":38.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":208108,"id":"CVE-2026-89537","ts":1789922711075,"field":"cvss","old":"6.4","new":"7"},{"seq":208107,"id":"CVE-2026-89537","ts":1789922711075,"field":"severity","old":"medium","new":"high"},{"seq":202887,"id":"CVE-2026-89537","ts":1789403732814,"field":"cvss","old":"9.1","new":"6.4"},{"seq":202886,"id":"CVE-2026-89537","ts":1789403732814,"field":"severity","old":"critical","new":"medium"},{"seq":197953,"id":"CVE-2026-89537","ts":1789384321120,"field":"cvss","old":"6.4","new":"9.1"},{"seq":197952,"id":"CVE-2026-89537","ts":1789384321120,"field":"severity","old":"medium","new":"critical"},{"seq":183486,"id":"CVE-2026-89537","ts":1789356675568,"field":"cvss","old":"9.1","new":"6.4"},{"seq":183485,"id":"CVE-2026-89537","ts":1789356675568,"field":"severity","old":"critical","new":"medium"},{"seq":153334,"id":"CVE-2026-89537","ts":1789285350089,"field":"cvss","old":null,"new":"9.1"},{"seq":153333,"id":"CVE-2026-89537","ts":1789285350089,"field":"severity","old":"none","new":"critical"},{"seq":147798,"id":"CVE-2026-89537","ts":1789270212330,"field":"cvss","old":null,"new":"6.4"},{"seq":147797,"id":"CVE-2026-89537","ts":1789270212330,"field":"severity","old":"none","new":"medium"},{"seq":109552,"id":"CVE-2026-89537","ts":1789183732386,"field":"cvss","old":null,"new":"6.4"},{"seq":109551,"id":"CVE-2026-89537","ts":1789183732386,"field":"severity","old":"none","new":"medium"}]}