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VulnerabilityPublished Updated

CVE-2025-40047: Linux kernel · io_uring/waitid: always prune wait queue entry in io_waitid_wait()

Affects Linux kernelSource GCVE Database

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Not known to be exploited · CVSS 7.8 High · fixed in 6.8.0-1050.53~22.04.1 : patch Linux kernel soon.

Data as of 3 Nov 2026, 17:49 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 6.8.0-1050.53~22.04.1, 6.8.0-1051.57~22.04.1, 6.8.0-1058.65~22.04.1 +38
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 28 Oct 2025

  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 to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 25.10linuxpkg:deb/ubuntu/linux?arch=source&distro=questingOther threatsAffected
  • <6.17.0-14.14
Fixed in
  • 6.17.0-14.14
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1007.7
Fixed in
  • 6.17.0-1007.7
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1008.8
Fixed in
  • 6.17.0-1008.8
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threatsAffected
  • 6.17.0-1003.3 – 6.17.0-1017.17
10 affected builds
Fixed in–
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1007.7
Fixed in
  • 6.17.0-1007.7
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1007.7
Fixed in
  • 6.17.0-1007.7

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and has been released in Linux kernel versions 6.8.0-1047.48~22.04.1 and later. Users and administrators should update affected Linux kernel versions to these fixed releases or newer to remediate the vulnerability. No additional mitigation steps are indicated by the vendor advisory beyond applying the official kernel updates.

Description

CVE-2025-40047 is a high-severity vulnerability in the Linux kernel's io_uring subsystem related to the wait queue entry pruning in the io_waitid_wait() function. The flaw involves a race condition where the wait queue entry is not always removed properly if a cancellation is in progress, potentially leading to system compromise. This issue affects multiple Linux kernel versions prior to 6.8.0-1050.53~22.04.1 and several specific older versions. The vulnerability has been addressed in Linux kernel versions 6.8.0-1047.48~22.04.1 and later. A patch is available and should be applied to mitigate the risk.

References

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