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VulnerabilityPublished

CVE-2026-99266: Linux kernel · io_uring/zcrx: fix buffer offsets in areas above 4GB

Affects Linux kernelSource CVE Database V5

0
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Not known to be exploited : upgrade to 51f4ee29bf0564e6ae7d3540693a9bc1dd2c8fd7 or 9bfb315e2d0907fbcaf5d0453dd6d873c9aa8d5b soon.

Data as of 3 Nov 2026, 12:13 UTC

Severity
High

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

Thin evidence

One scorer or none
Patch
Available – fixed in 51f4ee29bf0564e6ae7d3540693a9bc1dd2c8fd7, 9bfb315e2d0907fbcaf5d0453dd6d873c9aa8d5b

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 51f4ee29bf0564e6ae7d3540693a9bc1dd2c8fd7 or 9bfb315e2d0907fbcaf5d0453dd6d873c9aa8d5b.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 11ed914bbf948c4a37248f2876973ac18014056d, < 51f4ee29bf0564e6ae7d3540693a9bc1dd2c8fd7
Fixed in
  • 51f4ee29bf0564e6ae7d3540693a9bc1dd2c8fd7
LinuxLinuxAffected
  • ≥ 11ed914bbf948c4a37248f2876973ac18014056d, < 9bfb315e2d0907fbcaf5d0453dd6d873c9aa8d5b
Fixed in
  • 9bfb315e2d0907fbcaf5d0453dd6d873c9aa8d5b
LinuxLinuxAffected
  • =6.15
Fixed in–

AI-suggested

A fix for this vulnerability has been committed in the Linux kernel. Users should update to the fixed versions identified by commits 51f4ee29bf0564e6ae7d3540693a9bc1dd2c8fd7 and 9bfb315e2d0907fbcaf5d0453dd6d873c9aa8d5b. Applying these updates will resolve the buffer offset miscalculation issue. No additional mitigation steps are indicated by the vendor advisory.

Description

A vulnerability in the Linux kernel's io_uring subsystem affects buffer offset calculations for areas above 4GB. The flaw causes the completion queue entry (CQE) to point to incorrect buffer data located 4GB or multiples thereof below the actual data. This results in reading wrong data and returning a buffer not owned by the application, while the correct buffer is never returned.

References

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