{"id":"CVE-2026-89507","title":"kernel: RDMA/ucma: Lock the handler in ucma_write_cm_event() (CVE-2026-89507)","summary":"A flaw was found in the Linux kernel's RDMA/ucma component. A race condition exists in the `ucma_write_cm_event()` function where it re-reads a critical file pointer multiple times without proper locking. This allows another function, `ucm…","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-367","vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","affected":["openshift_container_platform 4"],"published":"2026-09-11","updated":"2026-09-16","sourceUpdated":"2026-09-16T10:28:26+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89507.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89507.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89507"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532319"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89507"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89507"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89507.mbox"},{"url":"https://git.kernel.org/stable/c/0be1955040a2eceed0ecfc387fdc92305411d273"},{"url":"https://git.kernel.org/stable/c/4f8bb11dd2ff365e7cff1c9964ab4607292d364e"},{"url":"https://git.kernel.org/stable/c/f4cc21c6a8e9d392871477f9fd98d68e5ad80272"}],"tags":["csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00127,"epssPercentile":0.02719,"scores":{"vendor":4.7,"cna":7.8},"ingestedAt":"2026-09-14T15:23:07.475Z","slug":"CVE-2026-89507","body":"## Overview\n\nA flaw was found in the Linux kernel's RDMA/ucma component. A race condition exists in the `ucma_write_cm_event()` function where it re-reads a critical file pointer multiple times without proper locking. This allows another function, `ucma_migrate_id()`, to change the file pointer mid-operation. An unprivileged local user can exploit this to cause list corruption, trigger a kernel crash, and leave a mutex locked indefinitely, resulting in a denial of service.\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-2026-89507.json)\n\n**kernel: RDMA/ucma: Lock the handler in ucma_write_cm_event()** — 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\nNot affected:\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\n## Remediation\n\nAffected","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":205468,"id":"CVE-2026-89507","ts":1789576721355,"field":"cvss","old":"4.7","new":"5.5"},{"seq":203030,"id":"CVE-2026-89507","ts":1789403733418,"field":"cvss","old":"7.8","new":"4.7"},{"seq":203029,"id":"CVE-2026-89507","ts":1789403733418,"field":"severity","old":"high","new":"medium"},{"seq":198004,"id":"CVE-2026-89507","ts":1789384321336,"field":"cvss","old":"4.7","new":"7.8"},{"seq":198003,"id":"CVE-2026-89507","ts":1789384321336,"field":"severity","old":"medium","new":"high"},{"seq":183781,"id":"CVE-2026-89507","ts":1789356677361,"field":"cvss","old":"7.8","new":"4.7"},{"seq":183780,"id":"CVE-2026-89507","ts":1789356677361,"field":"severity","old":"high","new":"medium"},{"seq":153298,"id":"CVE-2026-89507","ts":1789285349937,"field":"cvss","old":null,"new":"7.8"},{"seq":153297,"id":"CVE-2026-89507","ts":1789285349937,"field":"severity","old":"none","new":"high"},{"seq":147391,"id":"CVE-2026-89507","ts":1789270210721,"field":"cvss","old":null,"new":"4.7"},{"seq":147390,"id":"CVE-2026-89507","ts":1789270210721,"field":"severity","old":"none","new":"medium"},{"seq":109139,"id":"CVE-2026-89507","ts":1789183730462,"field":"cvss","old":null,"new":"4.7"},{"seq":109138,"id":"CVE-2026-89507","ts":1789183730462,"field":"severity","old":"none","new":"medium"}]}