{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "0a3a809089eb1d4a0a2fd0c16b520d603988c859"
            },
            {
              "fixed": "84a93b4e012587d0a4a84ffb23ec6da18e9d85f9"
            },
            {
              "fixed": "73fde8fe4469f4ed8f0afcc0b9d6413002a9e6b3"
            },
            {
              "fixed": "e54ad693eddb40c595add013f545354c538e325b"
            },
            {
              "fixed": "2857dcbd03cf3354af0fba1b65c6a260fb43811a"
            },
            {
              "fixed": "da4471557f279d0f56605158a625bb6e49ef7d41"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "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-2026-80849.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp-ao: fix use-after-free of current_key on reconnect to another peer\n\ntcp_inbound_ao_hash() is called before bh_lock_sock_nested() is taken,\nwith only rcu_read_lock() held. On the fast path for established\nsockets, if the rnext_keyid sent by the peer differs from\ncurrent_key-\u003esndid, the key the peer asked for is looked up and stored\nin current_key. The lookup is inside the RCU read side, but current_key\noutlives it.\n\nWhen the socket is disconnected and connect() is called again for\nanother peer, tcp_ao_connect_init() unlinks every key that does not\nmatch the new peer and frees it with call_rcu(). If current_key points\nat such a key, it is cleared to NULL.\n\nThe fast path reads sk_state only once on entry, so a softirq that got\ninto it while the socket was still established can update current_key\nafter that loop has already run. The update is inside the RCU read side,\nso it comes before the call_rcu() callback, and once the callback frees\nthe key, current_key is left pointing at freed memory.\n\nThe next transmission picks that pointer up in tcp_get_current_key().\ntcp_ao_transmit_skb() then reads the traffic key from the freed object,\nwhich is the use-after-free.\n\nWait for one grace period before unlinking, and only if a key is going\nto be removed. By the time tcp_connect() runs the socket is already in\nTCP_SYN_SENT, and TCP_AO_ESTABLISHED does not contain TCPF_SYN_SENT, so\na softirq entering after the wait cannot reach the fast path, and the\nones already in it have finished. The existing NULL handling in the loop\nis then enough.",
  "id": "CVE-2026-80849",
  "modified": "2026-09-06T03:30:51.921357413Z",
  "published": "2026-09-04T15:54:59.412Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2857dcbd03cf3354af0fba1b65c6a260fb43811a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/73fde8fe4469f4ed8f0afcc0b9d6413002a9e6b3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/84a93b4e012587d0a4a84ffb23ec6da18e9d85f9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/da4471557f279d0f56605158a625bb6e49ef7d41"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e54ad693eddb40c595add013f545354c538e325b"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80849.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80849"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "net/tcp-ao: fix use-after-free of current_key on reconnect to another peer"
}