{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "67a900cc0436d74e7ff89042371760def087680d"
            },
            {
              "fixed": "0fe6455b8e1a22414f39c07bc90a1df12b52ec74"
            },
            {
              "fixed": "9a65860959db594dfc1820c7fdc09285fb7556bf"
            },
            {
              "fixed": "594c90b197141944f25991b8314de5c26ee27a7e"
            },
            {
              "fixed": "c6d3bcb0f934d4297ac5fa1c8656ae40694fb601"
            },
            {
              "fixed": "825de39f0c35a112148799b3cbe45af3766c018a"
            },
            {
              "fixed": "bf6e8af2c8be77489bedeae9f8a9654cb710e500"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.2.0"
            },
            {
              "fixed": "6.1.178"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.145"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.97"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.40"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72444.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nflow_dissector: check device type before reading ETH_ADDRS\n\n__skb_flow_dissect() unconditionally reads 12 bytes from eth_hdr(skb)\nwhen FLOW_DISSECTOR_KEY_ETH_ADDRS is requested. This assumes the skb\nhas a valid Ethernet header at mac_header, which is not always the case.\n\nThe problem can be triggered by:\n 1. Creating a TUN device in L3 mode (IFF_TUN, hard_header_len=0)\n 2. Attaching a multiq qdisc with a flower filter matching on eth_src\n 3. Sending a packet through AF_PACKET\n\nSince TUN in L3 mode has no link-layer header, mac_header points to\nthe L3 data area. The flow dissector reads 12 bytes of uninitialized\nskb memory, which then propagates through fl_set_masked_key() and is\nused as a rhashtable lookup key in __fl_lookup(), as reported by KMSAN.\n\nRejecting the filter in the control path (at tc filter add time) is\nnot feasible because TC filter blocks can be shared between arbitrary\ndevices -- a filter installed on an Ethernet device may later classify\npackets on a headerless device through a shared block. The device\nassociation is not fixed at filter creation time.\n\nFix this by gating the memcpy on dev-\u003etype == ARPHRD_ETHER, which\nensures only true Ethernet-framed packets have their addresses read.\nThis is more precise than the previous hard_header_len \u003e= 12 check,\nwhich would incorrectly pass for non-Ethernet link types like IPoIB\n(ARPHRD_INFINIBAND, hard_header_len=24) and FDDI (hard_header_len=21)\nwhose L2 headers are not in Ethernet format. Additionally check\nskb_mac_header_was_set() to guard against the pathological case where\nmac_header is the unset sentinel (~0U), which would cause eth_hdr() to\nreturn a wild pointer.\n\nFor the act_mirred redirect case (Ethernet packet redirected to a\nnon-Ethernet device sharing a TC block), zeroing the key is the correct\nbehavior: the packet is now being classified on the target device, where\nEthernet address matching is not semantically meaningful.\n\nNote: on non-Ethernet devices, the zeroed key will match a filter\nconfigured with all-zero MAC addresses. This is an improvement over the\nprevious behavior where uninitialized memory could randomly match any\nfilter.",
  "id": "CVE-2026-72444",
  "modified": "2026-08-18T03:31:01.651274119Z",
  "published": "2026-08-15T05:56:55.229Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0fe6455b8e1a22414f39c07bc90a1df12b52ec74"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/594c90b197141944f25991b8314de5c26ee27a7e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/825de39f0c35a112148799b3cbe45af3766c018a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9a65860959db594dfc1820c7fdc09285fb7556bf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bf6e8af2c8be77489bedeae9f8a9654cb710e500"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c6d3bcb0f934d4297ac5fa1c8656ae40694fb601"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72444.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72444"
    },
    {
      "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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "flow_dissector: check device type before reading ETH_ADDRS"
}