{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "07afe1ba288c04280622fa002ed385f1ac0b6fe6"
            },
            {
              "fixed": "da1f5aa7ec93f2cc17f5cd30efc54f62af433cf2"
            },
            {
              "fixed": "916ec741e65af072b98e475feaad98c063da1b7c"
            },
            {
              "fixed": "1b466746fe109127fd983100a228cdd1f1f6ece2"
            },
            {
              "fixed": "2b46baa591d0a7c16b62f150917187e70d053be6"
            },
            {
              "fixed": "f12c2de4f542e3220e17e0606f492110064f04cb"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.8.0"
            },
            {
              "fixed": "6.12.108"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.49"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.13"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "7.2.0"
            },
            {
              "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-2026-80839.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: reject unrepresentable multicast TVLV offsets\n\nThe network and transport header fields in struct sk_buff are 16-bit\noffsets from skb-\u003ehead, and U16_MAX is reserved as the unset transport\nheader value. batadv_tvlv_call_handler() sets both fields from a received\nmulticast TVLV without checking whether the TVLV end is representable.\n\nIf the end offset exceeds the field's range, skb_set_transport_header()\ntruncates it so that the transport header precedes the network header.\nThe negative difference is then returned by skb_network_header_len() as\na large u32. batadv_mcast_forw_packet() consequently accepts an oversized\nmulticast tracker and accesses memory beyond the skb data.\n\nAdd skb_set_transport_header_careful(), an offset-aware counterpart to\nskb_reset_transport_header_careful(), which validates the final\nhead-relative offset before assigning it. Use the new helper in\nbatadv_tvlv_call_handler() and reject unrepresentable TVLVs before\nsetting the network header.",
  "id": "CVE-2026-80839",
  "modified": "2026-09-06T03:30:33.407216266Z",
  "published": "2026-09-04T15:54:49.378Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1b466746fe109127fd983100a228cdd1f1f6ece2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2b46baa591d0a7c16b62f150917187e70d053be6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/916ec741e65af072b98e475feaad98c063da1b7c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/da1f5aa7ec93f2cc17f5cd30efc54f62af433cf2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f12c2de4f542e3220e17e0606f492110064f04cb"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80839.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80839"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "batman-adv: reject unrepresentable multicast TVLV offsets"
}