{"id":"CVE-2026-89538","title":"kernel: SUNRPC: Reject krb5 v2 wrap tokens with oversized ec field (CVE-2026-89538)","summary":"A flaw was found in the Linux kernel's Server Unix Remote Procedure Call (SUNRPC) component. A remote attacker, with a valid Generic Security Service (GSS) context, could send a specially crafted Kerberos v2 wrap token with an oversized \"e…","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-131","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":"2026-09-18T21:56:06+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89538.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89538.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89538"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532114"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89538"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89538"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89538.mbox"},{"url":"https://git.kernel.org/stable/c/ac9efc29346b6942e71f0e24a3178a9121330fab"},{"url":"https://git.kernel.org/stable/c/b5746095b59f4d11f39f08751d36bbdfd1e5deac"},{"url":"https://git.kernel.org/stable/c/9fc6d6e6db49ab55208d5dd1c424c1d0d9aa7296"},{"url":"https://git.kernel.org/stable/c/4abb44a29bb515df6f49123848765c70fc9b5021"},{"url":"https://git.kernel.org/stable/c/dfcd81ab45613d45996fbf483d4ef54b0ec90ab9"},{"url":"https://git.kernel.org/stable/c/1f9856af065b6158271687e9788407b9573fd16f"},{"url":"https://git.kernel.org/stable/c/880effc943ed82d6811f272ed3307c222b40f4d6"},{"url":"https://git.kernel.org/stable/c/ad484748eec0a66eac0f13ab53b3fbedb7333c91"}],"tags":["csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00704,"epssPercentile":0.51875,"scores":{"vendor":7,"cna":9.8},"ingestedAt":"2026-09-14T15:23:07.452Z","slug":"CVE-2026-89538","body":"## Overview\n\nA flaw was found in the Linux kernel's Server Unix Remote Procedure Call (SUNRPC) component. A remote attacker, with a valid Generic Security Service (GSS) context, could send a specially crafted Kerberos v2 wrap token with an oversized \"extra count\" (ec) field. This improper handling of malformed tokens could lead to the buffer being left in a semantically invalid state, potentially causing a denial of service or other unpredictable behavior within the system.\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-2026-89538.json)\n\n**kernel: SUNRPC: Reject krb5 v2 wrap tokens with oversized ec field** — 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":208110,"id":"CVE-2026-89538","ts":1789922711599,"field":"cvss","old":"9.8","new":"7"},{"seq":208109,"id":"CVE-2026-89538","ts":1789922711599,"field":"severity","old":"critical","new":"high"},{"seq":197963,"id":"CVE-2026-89538","ts":1789384321170,"field":"cvss","old":"5.3","new":"9.8"},{"seq":197962,"id":"CVE-2026-89538","ts":1789384321170,"field":"severity","old":"medium","new":"critical"},{"seq":183758,"id":"CVE-2026-89538","ts":1789356677264,"field":"cvss","old":"9.8","new":"5.3"},{"seq":183757,"id":"CVE-2026-89538","ts":1789356677264,"field":"severity","old":"critical","new":"medium"},{"seq":153336,"id":"CVE-2026-89538","ts":1789285350097,"field":"cvss","old":null,"new":"9.8"},{"seq":153335,"id":"CVE-2026-89538","ts":1789285350097,"field":"severity","old":"none","new":"critical"},{"seq":147772,"id":"CVE-2026-89538","ts":1789270212230,"field":"cvss","old":null,"new":"5.3"},{"seq":147771,"id":"CVE-2026-89538","ts":1789270212230,"field":"severity","old":"none","new":"medium"},{"seq":109526,"id":"CVE-2026-89538","ts":1789183732286,"field":"cvss","old":null,"new":"5.3"},{"seq":109525,"id":"CVE-2026-89538","ts":1789183732286,"field":"severity","old":"none","new":"medium"}]}