Skip to main content
VulnerabilityPublished Updated

CVE-2026-52933: Linux kernel · io_uring/poll: fix signed comparison in io_poll_get_ownership()

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in fc47043f3d9af3efa407665b47f8378ec691ba18 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in fc47043f3d9af3efa407665b47f8378ec691ba18, ea0697129807d718037f618221037aa0660ee3c5, cf522703d4f194991615763697ae25a3f9539763 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 24 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • >=5.15.82 <5.16
  • >=6.0.11 <6.1
Fixed in
  • fc47043f3d9af3efa407665b47f8378ec691ba18
  • ea0697129807d718037f618221037aa0660ee3c5
  • cf522703d4f194991615763697ae25a3f9539763
  • c6d191164dc81838d8dbf452a6000f68c558d1ae
  • 326941b22806cbf2df1fbfe902b7908b368cce42
  • 81bf96b0abbfa4cd47ea32e12596aed3855fb2f3
  • 6.1
  • 5.16
LinuxLinuxAffected
  • =6.1
Fixed in–

Description

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.

References

Community reviews

Loading reviews…