{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "899bea8248cee35d54760a5e7d61a76af8e64411"
            },
            {
              "fixed": "596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5"
            },
            {
              "fixed": "aa5d5f8e502318e783545ba5d04bb40130b83e20"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.2.0"
            },
            {
              "fixed": "7.2.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99042.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/net: populate CONNECT filter fields for 24-byte sockaddr_in6\n\nio_connect_bpf_populate() fills connect.port and connect.v6_addr for\nAF_INET6 only when addr_len \u003e= sizeof(struct sockaddr_in6), i.e. 28\nbytes.\n\nThe IPv6 connect paths accept SIN6_LEN_RFC2133 (24 bytes), which\nalready holds sin6_port and sin6_addr. io_connect() passes addr_len to\nthe socket layer unchanged.\n\nAt addr_len 24 the filter sees family AF_INET6 with port and address\nzero, while the kernel connects to the real destination. A filter that\ndenies an IPv6 port or address is bypassed. Denying connect.port == P\nrejects [::1]:P with -EACCES at addr_len 28 but connects at addr_len 24.\n\nUse SIN6_LEN_RFC2133 as the threshold. sin6_scope_id stays zero when\nabsent.\n\nThe threshold mismatch was found by an AI coding assistant (Claude Code)\ncomparing this hook against the net/ipv6 length checks on my\ninstructions; it also drafted the reproducer and this patch. I verified\nthe bypass and the fix in a VM on 7.3-rc6 and that 7.2 has the same\ncode.",
  "id": "CVE-2026-99042",
  "modified": "2026-10-28T02:30:23.173690932Z",
  "published": "2026-10-23T12:22:01.804Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/aa5d5f8e502318e783545ba5d04bb40130b83e20"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99042.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99042"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "io_uring/net: populate CONNECT filter fields for 24-byte sockaddr_in6"
}