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VulnerabilityPublished Updated

CVE-2026-53397: Linux kernel · nfsd: fix posix_acl leak on SETACL decode failure

Affects Linux kernelSource GCVE Database

0
Authoritative record:CVE-2026-53397· High 7.5

Not known to be exploited · CVSS 7.5 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.

Data as of 28 Oct 2026, 12:35 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +59
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Jul 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
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-31.31
Fixed in
  • 7.0.0-31.31
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1012.12
Fixed in
  • 7.0.0-1012.12
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1014.14
Fixed in
  • 7.0.0-1014.14
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1013.13
Fixed in
  • 7.0.0-1013.13
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1011.11
Fixed in
  • 7.0.0-1011.11
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1006.7
Fixed in
  • 7.0.0-1006.7

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 should be applied to affected Linux kernel versions. The fix properly releases allocated posix_acl objects on all code paths, including decode failures, preventing the memory leak. Users should update to one of the fixed kernel versions listed in the established facts. No additional mitigation is required beyond applying the official fix.

Description

A vulnerability in the Linux kernel's NFS server (nfsd) causes a memory leak of posix_acl structures when decoding SETACL requests fails. This occurs because the cleanup function for these ACL objects is not called on decode failure, leading to resource leakage for the lifetime of the server process. The issue affects multiple Linux kernel versions prior to fixed releases in the 5.15 series and some older versions. The flaw has been assigned CVE-2026-53397 and is rated high severity with a CVSS score of 7.5. A patch is available that properly releases the allocated ACL objects on all code paths, including decode failures.

References

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