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VulnerabilityPublished Updated

CVE-2025-37954: Linux kernel · smb: client: Avoid race in open_cached_dir with lease breaks

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 7.5 High · fixed in 5.15.0-1096.105~20.04.1 : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 30% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 5.15.0-1096.105~20.04.1, 5.15.0-1114.123~20.04.1, 6.8.0-1046.49~22.04.1 +34
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 20 May 2025

  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 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threatsAffected
  • 6.17.0-1003.3 – 6.17.0-1017.17
10 affected builds
Fixed in–
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux@6.8.0-100.100?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-100.100
Fixed in
  • 6.8.0-100.100
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws@6.8.0-1046.49?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1046.49
Fixed in
  • 6.8.0-1046.49
Ubuntu 24.04 LTSlinux-aws-6.14pkg:deb/ubuntu/linux-aws-6.14@6.14.0-1011.11~24.04.1?arch=source&distro=nobleOther threatsAffected
  • <6.14.0-1011.11~24.04.1
Fixed in
  • 6.14.0-1011.11~24.04.1
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure@6.8.0-1038.44?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1038.44
Fixed in
  • 6.8.0-1038.44
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11@6.11.0-1018.18~24.04.1?arch=source&distro=nobleOther threatsAffected
  • 6.11.0-1008.8~24.04.1 – 6.11.0-1018.18~24.04.1
7 affected builds
Fixed in–

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 included in Linux kernel updates released by vendors such as Ubuntu (see USN-7699-1). Users should apply the official kernel updates and reboot their systems to ensure the vulnerability is remediated. Due to ABI changes, recompilation and reinstallation of third-party kernel modules may be required after updating. No additional mitigations are specified by the vendor advisory.

Description

A race condition vulnerability in the Linux kernel SMB client component was resolved. The flaw involved a race in open_cached_dir with lease breaks, potentially causing a dentry reference leak. This issue was fixed by extending the holding of the cfid_list_lock during directory caching operations. The vulnerability affects multiple Linux kernel versions and has a CVSS score of 7.5, indicating a medium severity. A patch is available and included in recent Linux kernel updates. Users should update their systems and reboot to apply the fix.

References

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