{"id":"CVE-2026-89603","title":"kernel: entry: Fix seccomp bypass after ptrace with TSYNC (CVE-2026-89603)","summary":"A flaw was found in the Linux kernel. A race condition exists where a seccomp filter, intended to restrict system calls, can be bypassed by an unprivileged process. This occurs when a thread is stopped for tracing (ptrace) and another thre…","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-367","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":"2026-09-15","sourceUpdated":"2026-09-15T12:45:58+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89603.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89603.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89603"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532493"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89603"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89603"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89603.mbox"},{"url":"https://git.kernel.org/stable/c/eca5ed4200f0be3e91f8a237b1f37582030a93a8"},{"url":"https://git.kernel.org/stable/c/8709e7e1dd7d7de0651e61700edf24f5784f9243"},{"url":"https://git.kernel.org/stable/c/22bb836fc133331982c264227a899d4b26a09706"},{"url":"https://git.kernel.org/stable/c/23001ee5d8631e30192cde6f6d3ccb6805570499"},{"url":"https://git.kernel.org/stable/c/09e8880ce5409bdb84da991b053d7087502c181e"},{"url":"https://git.kernel.org/stable/c/459f33f82864723a7fa366cf1091d9c6c893b6b2"},{"url":"https://git.kernel.org/stable/c/ab4647459098a43e9d6fdb860836f08c962f3774"},{"url":"https://git.kernel.org/stable/c/4a3591287fb7f808e209b4974ed337f609a2006b"}],"tags":["csaf","vex","red-hat","cve.org"],"epss":0.00142,"epssPercentile":0.03908,"scores":{"vendor":7,"cna":8.4},"ingestedAt":"2026-09-14T15:23:07.451Z","slug":"CVE-2026-89603","body":"## Overview\n\nA flaw was found in the Linux kernel. A race condition exists where a seccomp filter, intended to restrict system calls, can be bypassed by an unprivileged process. This occurs when a thread is stopped for tracing (ptrace) and another thread attempts to apply a seccomp filter with the `SECCOMP_FILTER_FLAG_TSYNC` flag. Due to a caching issue, the newly installed filter is not properly enforced, allowing the unprivileged process to execute system calls that should have been blocked, potentially leading to a security bypass.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · 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 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89603.json)\n\n**kernel: entry: Fix seccomp bypass after ptrace with TSYNC** — rated Important by Red Hat. Released 2026-09-11, updated 2026-09-15.\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,"exploitation":0,"ransomware":0},"changes":[{"seq":203887,"id":"CVE-2026-89603","ts":1789490211386,"field":"cvss","old":"8.4","new":"7"},{"seq":197870,"id":"CVE-2026-89603","ts":1789384320750,"field":"cvss","old":"7.8","new":"8.4"},{"seq":183421,"id":"CVE-2026-89603","ts":1789356675301,"field":"cvss","old":"8.4","new":"7.8"},{"seq":153426,"id":"CVE-2026-89603","ts":1789285350464,"field":"cvss","old":null,"new":"8.4"},{"seq":153425,"id":"CVE-2026-89603","ts":1789285350464,"field":"severity","old":"none","new":"high"},{"seq":147107,"id":"CVE-2026-89603","ts":1789270195200,"field":"cvss","old":null,"new":"7.8"},{"seq":147106,"id":"CVE-2026-89603","ts":1789270195200,"field":"severity","old":"none","new":"high"},{"seq":108866,"id":"CVE-2026-89603","ts":1789183729318,"field":"cvss","old":null,"new":"7.8"},{"seq":108865,"id":"CVE-2026-89603","ts":1789183729318,"field":"severity","old":"none","new":"high"}]}