{"id":"CVE-2026-98591","title":"kernel: bpf: Fix bounds check for skb-backed dynptrs (CVE-2026-98591)","summary":"A flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) subsystem. An integer underflow in the bounds-checking logic for network packet buffer pointers allows validation checks to pass incorrectly. A local user capable of runni…","severity":"medium","cvss":6.7,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H","cvssSource":"vendor","cwe":"CWE-191","vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","affected":["enterprise_linux 10"],"published":"2026-10-18","updated":"2026-10-20","sourceUpdated":"2026-10-20T04:44:02+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98591.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98591.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-98591"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2554923"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98591"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98591"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98591.mbox"},{"url":"https://git.kernel.org/stable/c/1b923538598be768e9f2f258a77a083d00e0c78b"},{"url":"https://git.kernel.org/stable/c/37877a24758068742fef687a7cf5362360dde1d1"},{"url":"https://git.kernel.org/stable/c/1196903a27cac5c929c7517e987a8d159f20c5e5"},{"url":"https://git.kernel.org/stable/c/39ffceaddb10753eac12785dba6ac0673860b4ac"},{"url":"https://git.kernel.org/stable/c/ed6eec97b534979dcf28b40c389cee57bd6561d4"}],"tags":["csaf","vex","red-hat","cve.org"],"epss":0.00201,"epssPercentile":0.09869,"ingestedAt":"2026-10-18T15:45:12.250Z","slug":"CVE-2026-98591","body":"## Overview\n\nA flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) subsystem. An integer underflow in the bounds-checking logic for network packet buffer pointers allows validation checks to pass incorrectly. A local user capable of running BPF programs could exploit this flaw to create pointers referencing invalid memory, potentially leading to out-of-bounds memory access, a denial of service (system crash), or privilege escalation.\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 2026-10-20 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98591.json)\n\n**kernel: bpf: Fix bounds check for skb-backed dynptrs** — rated Moderate by Red Hat. Released 2026-10-18, updated 2026-10-20.\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":37,"depthScoreParts":{"impact":36.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":225726,"id":"CVE-2026-98591","ts":1792498387677,"field":"cvss","old":null,"new":"6.7"},{"seq":225725,"id":"CVE-2026-98591","ts":1792498387677,"field":"severity","old":"none","new":"medium"}]}