CVE-2025-21944: Linux kernel · ksmbd: fix bug on trap in smb2_lock
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 6.8.0-1039.41~22.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 16:10 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1039.41~22.04.1, 6.8.0-1036.42~22.04.1, 6.8.0-1040.42~22.04.1 +34
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 1 Apr 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 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?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.
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix bug on trap in smb2_lock If lock count is greater than 1, flags could be old value. It should be checked with flags of smb_lock, not flags. It will cause bug-on trap from locks_free_lock in error handling routine.
References
- ubuntu.com/security/CVE-2025-21944 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-21944 (opens in a new tab)
- git.kernel.org/linus/e26e2d2e15daf1ab33e0135caf2304a0cfa2744b (opens in a new tab)
- git.kernel.org/stable/c/11e0e74e14f1832a95092f2c98ed3b99f57797ee (opens in a new tab)
- git.kernel.org/stable/c/2b70e3ac79eacbdf32571f7af48dd81cdd957ca8 (opens in a new tab)
- git.kernel.org/stable/c/8994f0ce8259f812b4f4a681d8298c6ff682efaa (opens in a new tab)
- git.kernel.org/stable/c/dbcd7fdd86f77529210fe8978154a81cd479844c (opens in a new tab)
- git.kernel.org/stable/c/e26e2d2e15daf1ab33e0135caf2304a0cfa2744b (opens in a new tab)
- ubuntu.com/security/notices/USN-7605-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7606-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7605-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7628-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7764-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7765-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7766-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7767-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7779-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7767-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7764-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7790-1 (opens in a new tab)