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VulnerabilityPublished

CVE-2026-99252: Linux kernel · io_uring/mpscq: disable preemption while pushing

Affects Linux kernelSource CVE Database V5

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Not known to be exploited : upgrade to 8c94677e2b6145393d4c129fe0f5364b0e5000a5 when convenient.

Data as of 3 Nov 2026, 11:46 UTC

Severity
Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none
Patch
Available – fixed in 8c94677e2b6145393d4c129fe0f5364b0e5000a5

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 3 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: 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 3 Nov 2026.

What to do

Upgrade Linux kernel to 8c94677e2b6145393d4c129fe0f5364b0e5000a5.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 50cb44bd0d5f243919a06b17b1d979fdcd72cb2b, < 8c94677e2b6145393d4c129fe0f5364b0e5000a5
Fixed in
  • 8c94677e2b6145393d4c129fe0f5364b0e5000a5
LinuxLinuxAffected
  • =7.2
Fixed in–

AI-suggested

A fix is available and has been committed in the Linux kernel at commit 8c94677e2b6145393d4c129fe0f5364b0e5000a5. Users should update to a kernel version including this fix to resolve the issue. No additional mitigation steps are indicated.

Description

A vulnerability in the Linux kernel's io_uring multi-producer single-consumer queue (mpscq) was addressed by disabling preemption during the push operation. The issue involved a timing window where a producer could be preempted after updating the queue tail but before linking the new node, causing consumers to spin-wait inefficiently, especially when consumer and producer tasks had differing priorities on the same CPU. The fix involves adding preempt_disable()/preempt_enable() calls around the push to prevent this race condition.

References

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