{"id":"CVE-2026-80925","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nvlan: fix skb_under_panic and races when toggling HW VLAN offload\n\nToggling hardware VLAN TX offload (NETIF_F_HW_VLAN_CTAG_TX or\nNETIF_F_HW_VLAN_STAG_TX) on a lower dev…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nvlan: fix skb_under_panic and races when toggling HW VLAN offload\n\nToggling hardware VLAN TX offload (NETIF_F_HW_VLAN_CTAG_TX or\nNETIF_F_HW_VLAN_STAG_TX) on a lower dev…","severity":"medium","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b38d7a4bc9c17e1d437696da25f9fbc286614d9d","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b30fe4de285b9bdaf9508740191f69f7cd83b8fa","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1517d1996b5236fe69eccd9d253f725e06996eb1","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < a29f3b884ba50217e6f50414f568073221e2bb07","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 447cbe95ebb95392b5d8f6a01c0556826919ce23","Linux 2.6.12"],"published":"2026-09-09","updated":"2026-10-03","sourceUpdated":"2026-10-03T11:17:40.783","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-80925","references":[{"url":"https://git.kernel.org/stable/c/1517d1996b5236fe69eccd9d253f725e06996eb1","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/447cbe95ebb95392b5d8f6a01c0556826919ce23","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a29f3b884ba50217e6f50414f568073221e2bb07","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b30fe4de285b9bdaf9508740191f69f7cd83b8fa","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b38d7a4bc9c17e1d437696da25f9fbc286614d9d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80925.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-80925"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2531063"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80925"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80925"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80925.mbox"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00156,"epssPercentile":0.04725,"ingestedAt":"2026-09-11T16:45:47.924Z","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"],"slug":"CVE-2026-80925","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nvlan: fix skb_under_panic and races when toggling HW VLAN offload\n\nToggling hardware VLAN TX offload (NETIF_F_HW_VLAN_CTAG_TX or\nNETIF_F_HW_VLAN_STAG_TX) on a lower device invokes vlan_transfer_features(),\nwhich dynamically changed vlandev->hard_header_len.\n\nThis causes two issues:\n1. Lockless TX paths (e.g. packet_snd in af_packet.c, ip6_finish_output2)\n   read dev->hard_header_len without holding RTNL lock. Mutating\n   hard_header_len dynamically under RTNL creates a data race where upper\n   layers reserve insufficient headroom based on a stale hard_header_len,\n   resulting in skb_under_panic when vlan_dev_hard_header() is called.\n2. In addition, vlan_transfer_features() updated hard_header_len without\n   updating header_ops, causing a mismatch between allocated headroom\n   and header creation.\n\nAlways setting dev->hard_header_len = real_dev->hard_header_len and\ndev->needed_headroom = real_dev->needed_headroom + VLAN_HLEN unconditionally\nensures:\n- dev->hard_header_len remains 100% static and immutable at real_dev->hard_header_len,\n  eliminating all dynamic runtime updates and data races on hard_header_len.\n- Upper layers allocating skbs via LL_RESERVED_SPACE() will always reserve\n  sufficient headroom for software VLAN tag insertion (real_dev->hard_header_len +\n  real_dev->needed_headroom + VLAN_HLEN).\n- vlandev inherits real_dev->needed_tailroom so underlying trailer/padding/ICV\n  requirements are honored.\n- AF_PACKET SOCK_RAW network header offsets remain correctly aligned at\n  real_dev->hard_header_len.\n- vlan_header_ops is used unconditionally.\n\nNote to stable teams: Make sure to backport these commits:\n\ne16e960d55a4 (\"ipvlan: inherit needed_headroom and needed_tailroom from phy_dev\")\ncef51860becd (\"macvlan: inherit needed_headroom and needed_tailroom from lowerdev\")\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-10-20 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80925.json)","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":225645,"id":"CVE-2026-80925","ts":1792498332721,"field":"cvss","old":null,"new":"5.5"},{"seq":225644,"id":"CVE-2026-80925","ts":1792498332721,"field":"severity","old":"none","new":"medium"}]}