CVE-2025-37954: Linux kernel · smb: client: Avoid race in open_cached_dir with lease breaks
Affects Linux kernelSource GCVE Database
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 20 May 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux@6.8.0-100.100?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws@6.8.0-1046.49?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
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 threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure@6.8.0-1038.44?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
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 threats | Affected
| 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
- ubuntu.com/security/CVE-2025-37954 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-37954 (opens in a new tab)
- git.kernel.org/linus/3ca02e63edccb78ef3659bebc68579c7224a6ca2 (opens in a new tab)
- git.kernel.org/stable/c/2407265dc32bc8cc45b62a612c2a214ba9038e8b (opens in a new tab)
- git.kernel.org/stable/c/2ed98e89ebc2e1bc73534dc3c18cb7843a889ff9 (opens in a new tab)
- git.kernel.org/stable/c/3ca02e63edccb78ef3659bebc68579c7224a6ca2 (opens in a new tab)
- git.kernel.org/stable/c/571dcf3d27b24800c171aea7b5e04ff06d10e2e9 (opens in a new tab)
- ubuntu.com/security/notices/USN-7699-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7699-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7721-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7775-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7775-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7775-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7802-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7809-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8031-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-4 (opens in a new tab)