{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "49da7e64f33e80edffb1a9eeb230fa4c3f42dffb"
            },
            {
              "fixed": "4b9601595e8b6b5d18878cac0aeabc687d241111"
            },
            {
              "fixed": "67d58ab4f2ccf7145f3da07e025735a09c79de1b"
            },
            {
              "fixed": "180ff4c81faf01ec4e06082c9daa7c40518ead89"
            },
            {
              "fixed": "804b681002ead233abf49a3efd681f5468a835f9"
            },
            {
              "fixed": "af421e9aed3920c7ac88c24daa48606c7112feca"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.17.0"
            },
            {
              "fixed": "6.6.151"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.103"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.44"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74478.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\num: vector: fix use-after-free in vector_mmsg_rx()\n\nWhen vector_mmsg_rx() discards a packet whose overlay header fails\nverify_header(), it frees the skb and continues the loop:\n\n\tif (header_check \u003c 0) {\n\t\tdev_kfree_skb_irq(skb);\n\t\tvp-\u003eestats.rx_encaps_errors++;\n\t\tcontinue;\n\t}\n\nThe normal and short-packet paths fall through to the bottom of the\nloop body, which clears the consumed slot and advances the cursors:\n\n\t(*skbuff_vector) = NULL;\n\tmmsg_vector++;\n\tskbuff_vector++;\n\nThe verify_header() \u003c 0 path skips that via continue, so the freed skb\nis left in skbuff_vector[] and the cursors do not advance. The next\niteration reads the same slot, gets the freed skb, and frees it again,\nproducing a refcount underflow / use-after-free in the RX path.\n\nDiscard the slot the same way the other paths do before continuing.\n\nOnly transports whose verify_header() can return negative are affected:\nGRE and L2TPv3 do so on a cookie/session-id mismatch (raw/tap do not),\nso any peer on such a transport can trigger it without authentication.",
  "id": "CVE-2026-74478",
  "modified": "2026-08-17T03:36:16.458545963Z",
  "published": "2026-08-15T12:27:12.549Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/180ff4c81faf01ec4e06082c9daa7c40518ead89"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4b9601595e8b6b5d18878cac0aeabc687d241111"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/67d58ab4f2ccf7145f3da07e025735a09c79de1b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/804b681002ead233abf49a3efd681f5468a835f9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/af421e9aed3920c7ac88c24daa48606c7112feca"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74478.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74478"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "um: vector: fix use-after-free in vector_mmsg_rx()"
}