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VulnerabilityPublished Updated

CVE-2026-52906: Linux kernel · 9p: fix access mode flags being ORed instead of replaced

Affects Linux kernelSource GCVE Database

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Not known to be exploited · CVSS 7.7 High · fixed in 7.0.0-28.28~24.04.1 : patch Linux kernel soon.

Data as of 6 Nov 2026, 17:09 UTC

CVSS 3.1 base score
7.7High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 7.0.0-28.28~24.04.1, 7.0.0-27.27, 7.0.0-1008.8 +6
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 Jun 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 6 Nov 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
  • <7.0.0-27.27
Fixed in
  • 7.0.0-27.27
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1008.8
Fixed in
  • 7.0.0-1008.8
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1010.10
Fixed in
  • 7.0.0-1010.10
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1009.9
Fixed in
  • 7.0.0-1009.9
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1007.7
Fixed in
  • 7.0.0-1007.7
Ubuntu 26.04 LTSlinux-ibmpkg:deb/ubuntu/linux-ibm?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1009.9
Fixed in
  • 7.0.0-1009.9

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 7.0.0-28.28~24.04.1, 7.0.0-27.27, 7.0.0-1008.8, 7.0.0-1010.10, 7.0.0-1009.9, 7.0.0-1007.7, 7.0.0-1013.13, 7.0.0-1014.14, and 7.0.0-27.27.1. Users and administrators should update to these fixed versions to remediate the issue. No other mitigation is required as the fix addresses the root cause.

Description

CVE-2026-52906 is a vulnerability in the Linux kernel's 9p filesystem implementation where access mode flags were incorrectly combined using a bitwise OR instead of being replaced. This caused access mode checks to fail, resulting in the kernel using an invalid user ID for file identifier lookups. Consequently, root users could be prevented from performing privileged operations such as chown. The issue has been fixed by clearing the access mask before applying user-specified mount options.

References

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