{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2"
            },
            {
              "fixed": "1517d1996b5236fe69eccd9d253f725e06996eb1"
            },
            {
              "fixed": "a29f3b884ba50217e6f50414f568073221e2bb07"
            },
            {
              "fixed": "447cbe95ebb95392b5d8f6a01c0556826919ce23"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.12"
            },
            {
              "fixed": "6.18.51"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80925.json"
  },
  "details": "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 device invokes vlan_transfer_features(),\nwhich dynamically changed vlandev-\u003ehard_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-\u003ehard_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-\u003ehard_header_len = real_dev-\u003ehard_header_len and\ndev-\u003eneeded_headroom = real_dev-\u003eneeded_headroom + VLAN_HLEN unconditionally\nensures:\n- dev-\u003ehard_header_len remains 100% static and immutable at real_dev-\u003ehard_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-\u003ehard_header_len +\n  real_dev-\u003eneeded_headroom + VLAN_HLEN).\n- vlandev inherits real_dev-\u003eneeded_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-\u003ehard_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\")",
  "id": "CVE-2026-80925",
  "modified": "2026-09-12T03:30:28.995888718Z",
  "published": "2026-09-09T16:19:44.748Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1517d1996b5236fe69eccd9d253f725e06996eb1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/447cbe95ebb95392b5d8f6a01c0556826919ce23"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a29f3b884ba50217e6f50414f568073221e2bb07"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80925.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80925"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "vlan: fix skb_under_panic and races when toggling HW VLAN offload"
}