CVE-2025-38244: Linux kernel · smb: client: fix potential deadlock when reconnecting channels
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 6.8.0-1046.49~22.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 16% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1046.49~22.04.1, 6.8.0-1040.46~22.04.1, 6.8.0-1047.50~22.04.2 +32
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 9 Jul 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@6.14.0-1015.15~24.04.1?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure@6.8.0-1040.46?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 fix is available and has been released by Ubuntu and other Linux distributions. Users should apply the official Linux kernel updates that correct the lock ordering issue in the SMB client subsystem. After updating, a system reboot is required. For Ubuntu Azure kernel users, update to the specified patched kernel versions (e.g., linux-image-6.14.0-1013-azure 6.14.0-1013.13 or linux-image-6.8.0-1040-azure 6.8.0-1040.46 for 24.04 LTS). Recompilation and reinstallation of third-party kernel modules may be necessary due to ABI changes. No additional mitigation steps are indicated by the vendor advisory.
Description
A deadlock vulnerability in the Linux kernel's SMB client subsystem was resolved by fixing the lock acquisition order in the function cifs_signal_cifsd_for_reconnect. The issue could cause a circular locking dependency leading to a deadlock during channel reconnection. This vulnerability affects specific Linux kernel versions and has a CVSS score of 7.5, indicating a medium severity impact primarily causing denial of service (system hang). Official patches are available and included in updated Linux kernel packages for Ubuntu Azure and other distributions.
References
- ubuntu.com/security/CVE-2025-38244 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-38244 (opens in a new tab)
- git.kernel.org/linus/711741f94ac3cf9f4e3aa73aa171e76d188c0819 (opens in a new tab)
- git.kernel.org/stable/c/711741f94ac3cf9f4e3aa73aa171e76d188c0819 (opens in a new tab)
- git.kernel.org/stable/c/7f3ead8ebc0ef65b6c89a13912b4e80218425629 (opens in a new tab)
- git.kernel.org/stable/c/c82c7041258d96e3286f6790ab700e4edd3cc9e3 (opens in a new tab)
- git.kernel.org/stable/c/fe035dc78aa6ca8f862857d45beaf7a0e03206ca (opens in a new tab)
- ubuntu.com/security/notices/USN-7798-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7808-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7809-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7808-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7833-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7833-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7833-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7833-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7856-1 (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)