{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "c265ae75f900cea4e415230a77b5d152377627dd"
            },
            {
              "fixed": "417e02f7b6051765b91cf1289071882eebd172e0"
            },
            {
              "fixed": "2b8ad4981ecedb14c1fdd811ab977010b23933e6"
            },
            {
              "fixed": "ba77efee1b95b4ad7559b1cdbe7cd7fa36dca95b"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.18.0"
            },
            {
              "fixed": "6.18.50"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81009.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/query: cap user size passed to copy_struct_to_user\n\nio_handle_query_entry() clamps hdr.size for the inbound copy_from_user()\nbut keeps the original user value as usize. copy_struct_to_user() uses\nthat usize and, when it is larger than the kernel result, clear_user()s\nthe trailing bytes.\n\nAs hdr.size is a __u32, a query can request nearly 4 GiB of zeroing,\nincluding on the error path where res_size stays 0. The interface is\nreachable without a ring via IORING_REGISTER_QUERY.\n\nReject sizes larger than PAGE_SIZE, as recommended for copy_struct_*\ninterfaces.",
  "id": "CVE-2026-81009",
  "modified": "2026-09-13T03:30:21.958303603Z",
  "published": "2026-09-11T19:43:00.074Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2b8ad4981ecedb14c1fdd811ab977010b23933e6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/417e02f7b6051765b91cf1289071882eebd172e0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ba77efee1b95b4ad7559b1cdbe7cd7fa36dca95b"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81009.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-81009"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "io_uring/query: cap user size passed to copy_struct_to_user"
}