CVE-2025-40195: Linux kernel · mount: handle NULL values in mnt_ns_release()
Affects Linux kernelSource GCVE Database
Not known to be exploited · fixed in 6.17.0-1007.7~24.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 11:07 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.17.0-1007.7~24.04.1, 6.17.0-1008.8~24.04.1, 6.17.0-1008.8 +6
Exploitation evidence
Disclosed: evidence found.
CVE published 12 Nov 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 25.10linuxpkg:deb/ubuntu/linux@6.17.0-14.14?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1007.7?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1008.8?arch=source&distro=questingOther threats | 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 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1007.7?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1007.7?arch=source&distro=questingOther 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 has been released as part of the Ubuntu security update USN-8029-1. Users should update their Linux kernel to versions including or beyond the fixed releases to mitigate this vulnerability. No additional mitigation steps are required beyond applying the official kernel updates.
Description
A vulnerability in the Linux kernel's mount subsystem was resolved, specifically addressing the handling of NULL pointer values in the mnt_ns_release() function when called by listmount(). Improper handling of NULL pointers could lead to system instability or crashes. This issue has been fixed in updated Linux kernel versions. The fix is included in a broader security update addressing multiple kernel subsystems.
References
- ubuntu.com/security/CVE-2025-40195 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-40195 (opens in a new tab)
- git.kernel.org/linus/6c7ca6a02f8f9549a438a08a23c6327580ecf3d6 (opens in a new tab)
- git.kernel.org/stable/c/2d68f8a7379d9c61005e982600c61948d4d019bd (opens in a new tab)
- git.kernel.org/stable/c/6c7ca6a02f8f9549a438a08a23c6327580ecf3d6 (opens in a new tab)
- git.kernel.org/stable/c/99ae3e70a293834d0274c46a37120c71a24a4995 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8030-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8048-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-3 (opens in a new tab)