CVE-2025-38520: Linux kernel · drm/amdkfd: Don't call mmput from MMU notifier callback
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 6.8.0-1046.49~22.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 1% 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, 6.8.0-1051.57~22.04.1, 6.8.0-1047.50~22.04.2 +29
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 16 Aug 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@6.14.0-1017.17~24.04.1?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure@6.8.0-1046.52?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 should be applied to affected linux-hwe-edge kernel versions. The fix corrects the reference counting in the drm/amdkfd subsystem to prevent deadlocks and resource leaks. Users should update to patched kernel versions as listed in the affectedVersions field. No additional mitigation actions are indicated by the vendor advisory.
Description
A deadlock vulnerability in the Linux kernel's drm/amdkfd subsystem was resolved. The issue occurs when the mmput function is called from an MMU notifier callback during process exit, potentially causing a deadlock and leaking kernel file descriptor (kfd) processes and VRAM. The fix involves adjusting reference counting to prevent premature release of memory management structures during deferred work. This vulnerability affects specific versions of the linux-hwe-edge kernel and has a medium severity rating with a CVSS score of 5.5.
References
- ubuntu.com/security/CVE-2025-38520 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-38520 (opens in a new tab)
- git.kernel.org/linus/cf234231fcbc7d391e2135b9518613218cc5347f (opens in a new tab)
- git.kernel.org/stable/c/145a56bd68f4bff098d59fbc7c263d20dfef4fc4 (opens in a new tab)
- git.kernel.org/stable/c/a7eb0a25010a674c8fdfbece38353ef7be8c5834 (opens in a new tab)
- git.kernel.org/stable/c/c1bde9d48e09933c361521720f77a8072083c83a (opens in a new tab)
- git.kernel.org/stable/c/cf234231fcbc7d391e2135b9518613218cc5347f (opens in a new tab)
- git.kernel.org/stable/c/e90ee15ce28c61f6d83a0511c3e02e2662478350 (opens in a new tab)
- ubuntu.com/security/notices/USN-7879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7879-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7880-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7879-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7879-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7934-1 (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)
- ubuntu.com/security/notices/USN-8028-5 (opens in a new tab)