{"id":"CVE-2026-80905","title":"kernel: net: tap: fix wrong transport_header when sending VLAN-tagged frame (CVE-2026-80905)","summary":"A flaw was found in the kernel. When processing VLAN-tagged frames, the network header is incorrectly advanced past the VLAN tag before the transport header is probed. This misinterprets the inner protocol header as a VLAN header, resultin…","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-20","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","affected":["enterprise_linux 10","enterprise_linux 8","enterprise_linux 9","openshift_container_platform 4"],"published":"2026-09-04","updated":"2026-10-25","sourceUpdated":"2026-10-25T21:47:09+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80905.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80905.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-80905"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2528795"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80905"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80905"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80905.mbox"},{"url":"https://kernelcve.org/list/?q=CVE-2026-80905"},{"url":"https://git.kernel.org/stable/c/c0376820922d255ae1d103c32345a6ec4c3266f7"},{"url":"https://git.kernel.org/stable/c/f1d297cad5c1eacd9fadfd0346ad97405ffbf97c"},{"url":"https://git.kernel.org/stable/c/5ffaa5d7f56ab24a8e23cf131eadfef31a3bbc4b"},{"url":"https://git.kernel.org/stable/c/88b79ac89ecc04d7f2613f7e1c0b46f0c4ddb2f3"},{"url":"https://git.kernel.org/stable/c/cbb35cbe8db268fefe34c23df15348cf99025298"}],"tags":["csaf","vex","red-hat","cve.org"],"epss":0.00209,"epssPercentile":0.10937,"ingestedAt":"2026-10-21T12:48:53.748Z","slug":"CVE-2026-80905","body":"## Overview\n\nA flaw was found in the kernel. When processing VLAN-tagged frames, the network header is incorrectly advanced past the VLAN tag before the transport header is probed. This misinterprets the inner protocol header as a VLAN header, resulting in an uninitialized transport header. This issue can lead to incorrect packet dissection and potentially affect network functionality.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-25 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80905.json)\n\n**kernel: net: tap: fix wrong transport_header when sending VLAN-tagged frame** — rated Moderate by Red Hat. Released 2026-09-04, updated 2026-10-25.\n\nAffected:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 8\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 8\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\n## Remediation\n\nFix deferred\n\nWorkarounds / mitigations:\n\n- Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":229485,"id":"CVE-2026-80905","ts":1793019791896,"field":"cvss","old":null,"new":"5.5"},{"seq":229484,"id":"CVE-2026-80905","ts":1793019791896,"field":"severity","old":"none","new":"medium"}]}