GHSA-W7V4-JWP5-GR92

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

io_uring/nop: fix file reference leak with IOSQE_FIXED_FILE

NOP file-acquisition support choses between a fixed (registered) file and a normal fget()'d file based on its own IORING_NOP_FIXED_FILE flag in sqe->nop_flags. However, a request's REQ_F_FIXED_FILE is set independently from the generic IOSQE_FIXED_FILE sqe flag during request init, before the issue handler runs.

If a NOP is submitted with IOSQE_FIXED_FILE set (so REQ_F_FIXED_FILE is set) but without IORING_NOP_FIXED_FILE, io_nop() takes the normal path and grabs a real reference via io_file_get_normal(). On completion, io_put_file() only drops the reference when REQ_F_FIXED_FILE is clear, so the fget()'d file is never released and leaks:

BUG: memory leak unreferenced object 0xffff88800f42c240 (size 176): kmem_cache_alloc_noprof+0x358/0x440 alloc_empty_file+0x57/0x180 path_openat+0x44/0x1e50 do_file_open+0x121/0x200 do_sys_openat2+0xa7/0x150 __x64_sys_openat+0x82/0xf0

Decide between fixed and normal file acquisition from REQ_F_FIXED_FILE, the same way io_assign_file() does for every other opcode, and fold IORING_NOP_FIXED_FILE into REQ_F_FIXED_FILE at prep time.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-64426"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:26Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/nop: fix file reference leak with IOSQE_FIXED_FILE\n\nNOP file-acquisition support choses between a fixed (registered) file and\na normal fget()\u0027d file based on its own IORING_NOP_FIXED_FILE flag in\nsqe-\u003enop_flags. However, a request\u0027s REQ_F_FIXED_FILE is set\nindependently from the generic IOSQE_FIXED_FILE sqe flag during request\ninit, before the issue handler runs.\n\nIf a NOP is submitted with IOSQE_FIXED_FILE set (so REQ_F_FIXED_FILE is\nset) but without IORING_NOP_FIXED_FILE, io_nop() takes the normal path\nand grabs a real reference via io_file_get_normal(). On completion,\nio_put_file() only drops the reference when REQ_F_FIXED_FILE is clear,\nso the fget()\u0027d file is never released and leaks:\n\n  BUG: memory leak\n  unreferenced object 0xffff88800f42c240 (size 176):\n    kmem_cache_alloc_noprof+0x358/0x440\n    alloc_empty_file+0x57/0x180\n    path_openat+0x44/0x1e50\n    do_file_open+0x121/0x200\n    do_sys_openat2+0xa7/0x150\n    __x64_sys_openat+0x82/0xf0\n\nDecide between fixed and normal file acquisition from REQ_F_FIXED_FILE,\nthe same way io_assign_file() does for every other opcode, and fold\nIORING_NOP_FIXED_FILE into REQ_F_FIXED_FILE at prep time.",
  "id": "GHSA-w7v4-jwp5-gr92",
  "modified": "2026-07-25T12:31:35Z",
  "published": "2026-07-25T12:31:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64426"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2564ca2e31bd8ee8348362941af2ee4671e487ca"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/722869fcff598fad20d5ab79c305897a7534708b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7267717f35787167fcce4bc14f6ef3fa06682dcf"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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