{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "e990cef6516daa4e1e236433579e333f74fd38cb"
            },
            {
              "fixed": "2f55fa28011c97d6495d5787808db10a8c2d690d"
            },
            {
              "fixed": "e052f920773b73be49eb4d8702a9f85de7464363"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.13.0"
            },
            {
              "fixed": "7.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80634.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: flowtable: avoid num_encaps underflow on bridge VLAN untag\n\nThe DEV_PATH_BR_VLAN_UNTAG case post-decrements info-\u003enum_encaps\ninside WARN_ON_ONCE(). num_encaps is u8, so if it's already 0 the\ndecrement still happens and wraps it to 255. The break only leaves\nthe inner switch -- a later path entry can set info-\u003eindev back to\na real device, and we end up returning with num_encaps == 255.\n\nnft_dev_forward_path() then walks info.encap[] (size 2) up to\nnum_encaps, which means an OOB stack read and a bogus count copied\ninto the route descriptor.\n\nShould only happen on a malformed bridge path stack, hence the WARN,\nbut worth handling sanely. Move the decrement out of the WARN.\n\n[ While at this, remove the WARN_ON_ONCE since this can only happen\n  with a buggy bridge path stack --pablo ].",
  "id": "CVE-2026-80634",
  "modified": "2026-08-30T03:30:52.632174177Z",
  "published": "2026-08-28T06:48:49.022Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2f55fa28011c97d6495d5787808db10a8c2d690d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e052f920773b73be49eb4d8702a9f85de7464363"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80634.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80634"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "netfilter: flowtable: avoid num_encaps underflow on bridge VLAN untag"
}