GHSA-W44C-CV6C-X94C
Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-11 21:31In the Linux kernel, the following vulnerability has been resolved:
io_uring/query: cap user size passed to copy_struct_to_user
io_handle_query_entry() clamps hdr.size for the inbound copy_from_user() but keeps the original user value as usize. copy_struct_to_user() uses that usize and, when it is larger than the kernel result, clear_user()s the trailing bytes.
As hdr.size is a __u32, a query can request nearly 4 GiB of zeroing, including on the error path where res_size stays 0. The interface is reachable without a ring via IORING_REGISTER_QUERY.
Reject sizes larger than PAGE_SIZE, as recommended for copy_struct_* interfaces.
{
"affected": [],
"aliases": [
"CVE-2026-81009"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-11T20:19:09Z",
"severity": null
},
"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": "GHSA-w44c-cv6c-x94c",
"modified": "2026-09-11T21:31:24Z",
"published": "2026-09-11T21:31:24Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-81009"
},
{
"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"
}
],
"schema_version": "1.4.0",
"severity": []
}
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