CVE-2025-37776: Linux kernel · ksmbd: fix use-after-free in smb_break_all_levII_oplock()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.8 High.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 28% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 1 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
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@6.8.0-136.136?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws@6.8.0-1060.63?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure@6.8.0-1062.69?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– |
Ubuntu 24.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.8.0-1061.68?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 fix is available and included in updated Linux kernel releases as per the Ubuntu advisory USN-7594-1. Users should apply the official kernel updates provided by their distribution to remediate this vulnerability. No additional mitigation is required once patched.
Description
A use-after-free vulnerability in the Linux kernel's ksmbd component was fixed. The issue occurred in the smb_break_all_levII_oplock() function due to racy unlocking within a loop. The patch introduced a read lock to protect the entire loop, preventing the race condition. This vulnerability affects multiple specific Linux kernel versions. The vulnerability has a CVSS score of 8.8, indicating high severity. The Ubuntu security advisory confirms the fix is included in updated kernel releases.
References
- ubuntu.com/security/CVE-2025-37776 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-37776 (opens in a new tab)
- git.kernel.org/linus/18b4fac5ef17f77fed9417d22210ceafd6525fc7 (opens in a new tab)
- git.kernel.org/stable/c/18b4fac5ef17f77fed9417d22210ceafd6525fc7 (opens in a new tab)
- git.kernel.org/stable/c/296cb5457cc6f4a754c4ae29855f8a253d52bcc6 (opens in a new tab)
- git.kernel.org/stable/c/d54ab1520d43e95f9b2e22d7a05fc9614192e5a5 (opens in a new tab)
- git.kernel.org/stable/c/d73686367ad68534257cd88a36ca3c52cb8b81d8 (opens in a new tab)
- ubuntu.com/security/notices/USN-7594-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7594-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7594-3 (opens in a new tab)