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GHSA-37VF-C5QJ-3JR7

Vulnerability from github – Published: 2026-06-24 09:30 – Updated: 2026-09-08 09:35
VLAI
Details

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

io_uring/poll: fix signed comparison in io_poll_get_ownership()

io_poll_get_ownership() uses a signed comparison to check whether poll_refs has reached the threshold for the slowpath:

if (unlikely(atomic_read(&req->poll_refs) >= IO_POLL_REF_BIAS))

atomic_read() returns int (signed). When IO_POLL_CANCEL_FLAG (BIT(31)) is set in poll_refs, the value becomes negative in signed arithmetic, so the >= 128 comparison always evaluates to false and the slowpath is never taken.

Fix this by casting the atomic_read() result to unsigned int before the comparison, so that the cancel flag is treated as a large positive value and correctly triggers the slowpath.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-52933"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-835"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-24T08:16:23Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/poll: fix signed comparison in io_poll_get_ownership()\n\nio_poll_get_ownership() uses a signed comparison to check whether\npoll_refs has reached the threshold for the slowpath:\n\n    if (unlikely(atomic_read(\u0026req-\u003epoll_refs) \u003e= IO_POLL_REF_BIAS))\n\natomic_read() returns int (signed). When IO_POLL_CANCEL_FLAG\n(BIT(31)) is set in poll_refs, the value becomes negative in\nsigned arithmetic, so the \u003e= 128 comparison always evaluates to\nfalse and the slowpath is never taken.\n\nFix this by casting the atomic_read() result to unsigned int\nbefore the comparison, so that the cancel flag is treated as a\nlarge positive value and correctly triggers the slowpath.",
  "id": "GHSA-37vf-c5qj-3jr7",
  "modified": "2026-09-08T09:35:31Z",
  "published": "2026-06-24T09:30:48Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52933"
    },
    {
      "type": "WEB",
      "url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/326941b22806cbf2df1fbfe902b7908b368cce42"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/81bf96b0abbfa4cd47ea32e12596aed3855fb2f3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c6d191164dc81838d8dbf452a6000f68c558d1ae"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cf522703d4f194991615763697ae25a3f9539763"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ea0697129807d718037f618221037aa0660ee3c5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fc47043f3d9af3efa407665b47f8378ec691ba18"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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