{"id":"CVE-2026-89503","title":"kernel: ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page() (CVE-2026-89503)","summary":"A flaw was found in the Linux kernel's ring-buffer component. A race condition exists in the `ring_buffer_alloc_read_page()` function when it interacts with `ring_buffer_subbuf_order_set`. This can lead to an incorrect memory allocation wh…","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 Enterprise Linux 10","affected":["enterprise_linux 10"],"published":"2026-09-11","updated":"2026-09-14","sourceUpdated":"2026-09-14T08:20:09+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89503.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89503.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89503"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532017"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89503"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89503"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89503.mbox"},{"url":"https://git.kernel.org/stable/c/2dc510957fe8fd098ab3c3147ebdf34d00cd2734"},{"url":"https://git.kernel.org/stable/c/53106e9262a310ef2c9a9321168c03705940c678"},{"url":"https://git.kernel.org/stable/c/e743527c5bfdceda1095bc0a9e596e2aebb6a9c3"}],"tags":["csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00161,"epssPercentile":0.05759,"scores":{"vendor":5.5,"cna":7.8},"ingestedAt":"2026-09-14T15:23:07.475Z","slug":"CVE-2026-89503","body":"## Overview\n\nA flaw was found in the Linux kernel's ring-buffer component. A race condition exists in the `ring_buffer_alloc_read_page()` function when it interacts with `ring_buffer_subbuf_order_set`. This can lead to an incorrect memory allocation where the buffer page's order (`bpage->order`) does not match the actual allocated memory. This mismatch could potentially cause system instability or a denial of service.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10 · no fix planned: Red Hat Enterprise Linux 10 · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89503.json)\n\n**kernel: ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page()** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-14.\n\nAffected:\n\n- Red Hat Enterprise Linux 10\n\nNo fix planned:\n\n- Red Hat Enterprise Linux 10\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 Enterprise Linux 9\n- Red Hat OpenShift Container Platform 4\n\n## Remediation\n\nFix deferred","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":202807,"id":"CVE-2026-89503","ts":1789403724828,"field":"cvss","old":"7.8","new":"5.5"},{"seq":202806,"id":"CVE-2026-89503","ts":1789403724828,"field":"severity","old":"high","new":"medium"},{"seq":197990,"id":"CVE-2026-89503","ts":1789384321278,"field":"cvss","old":"5.5","new":"7.8"},{"seq":197989,"id":"CVE-2026-89503","ts":1789384321278,"field":"severity","old":"medium","new":"high"},{"seq":183504,"id":"CVE-2026-89503","ts":1789356675640,"field":"cvss","old":"7.8","new":"5.5"},{"seq":183503,"id":"CVE-2026-89503","ts":1789356675640,"field":"severity","old":"high","new":"medium"},{"seq":153294,"id":"CVE-2026-89503","ts":1789285349921,"field":"cvss","old":null,"new":"7.8"},{"seq":153293,"id":"CVE-2026-89503","ts":1789285349921,"field":"severity","old":"none","new":"high"},{"seq":109622,"id":"CVE-2026-89503","ts":1789183732683,"field":"cvss","old":null,"new":"5.5"},{"seq":109621,"id":"CVE-2026-89503","ts":1789183732683,"field":"severity","old":"none","new":"medium"}]}