{"id":"CVE-2026-89630","title":"kernel: smb: client: restore the data_offset bound in is_valid_oplock_break() (CVE-2026-89630)","summary":"A flaw was found in the Linux kernel's Server Message Block (SMB) client. An incorrect calculation of the `data_offset` bound in the `is_valid_oplock_break()` function can lead to a read overflow. This vulnerability allows a malicious SMB …","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 9","openshift_container_platform 4"],"published":"2026-09-11","updated":"2026-09-14","sourceUpdated":"2026-09-14T17:46:37+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89630.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89630.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89630"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532051"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89630"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89630"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89630.mbox"},{"url":"https://git.kernel.org/stable/c/5b16a1967a01ad4496a7206a87c3eb16f1df2b05"},{"url":"https://git.kernel.org/stable/c/ba22f575de9deeae4ae0859ca4315a7698226237"}],"tags":["csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00539,"epssPercentile":0.42865,"scores":{"vendor":6.3,"cna":9.1},"ingestedAt":"2026-09-14T15:23:07.474Z","slug":"CVE-2026-89630","body":"## Overview\n\nA flaw was found in the Linux kernel's Server Message Block (SMB) client. An incorrect calculation of the `data_offset` bound in the `is_valid_oplock_break()` function can lead to a read overflow. This vulnerability allows a malicious SMB server to potentially trigger an out-of-bounds read, which could result in information disclosure or a denial of service.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89630.json)\n\n**kernel: smb: client: restore the data_offset bound in is_valid_oplock_break()** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-14.\n\nAffected:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 9\n- Red Hat OpenShift Container Platform 4\n\nNo fix planned:\n\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 6\n- Red Hat Enterprise Linux 7\n- Red Hat Enterprise Linux 8\n- Red Hat OpenShift Container Platform 4\n\n## Remediation\n\nAffected","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":38.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":204223,"id":"CVE-2026-89630","ts":1789490240332,"field":"cvss","old":"6.3","new":"7"},{"seq":204222,"id":"CVE-2026-89630","ts":1789490240332,"field":"severity","old":"medium","new":"high"},{"seq":202851,"id":"CVE-2026-89630","ts":1789403732668,"field":"cvss","old":"9.1","new":"6.3"},{"seq":202850,"id":"CVE-2026-89630","ts":1789403732668,"field":"severity","old":"critical","new":"medium"},{"seq":197840,"id":"CVE-2026-89630","ts":1789384320619,"field":"cvss","old":"6.3","new":"9.1"},{"seq":197839,"id":"CVE-2026-89630","ts":1789384320619,"field":"severity","old":"medium","new":"critical"},{"seq":183391,"id":"CVE-2026-89630","ts":1789356675168,"field":"cvss","old":"9.1","new":"6.3"},{"seq":183390,"id":"CVE-2026-89630","ts":1789356675168,"field":"severity","old":"critical","new":"medium"},{"seq":153464,"id":"CVE-2026-89630","ts":1789285350615,"field":"cvss","old":null,"new":"9.1"},{"seq":153463,"id":"CVE-2026-89630","ts":1789285350615,"field":"severity","old":"none","new":"critical"},{"seq":147790,"id":"CVE-2026-89630","ts":1789270212300,"field":"cvss","old":null,"new":"6.3"},{"seq":147789,"id":"CVE-2026-89630","ts":1789270212300,"field":"severity","old":"none","new":"medium"},{"seq":109546,"id":"CVE-2026-89630","ts":1789183732362,"field":"cvss","old":null,"new":"6.3"},{"seq":109545,"id":"CVE-2026-89630","ts":1789183732362,"field":"severity","old":"none","new":"medium"}]}