CVE-2025-40195 mount: handle NULL values in mnt_ns_release()
A local attacker can cause a denial of service in the Linux kernel by triggering a NULL pointer dereference in the mount namespace release function.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-40195?
CVE-2025-40195 is a vulnerability in Linux, published on 12 Nov 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
mount: handle NULL values in mnt_ns_release()
When calling in listmount() mnt_ns_release() may be passed a NULL pointer. Handle that case gracefully.
Which versions are affected by CVE-2025-40195?
How do I fix CVE-2025-40195?
Apply the vendor's patch.
Is CVE-2025-40195 being exploited?
There is no known exploitation of CVE-2025-40195 in the wild and no public exploit code.
Sources
Also known as AZL-70076, BELL-CVE-2025-40195, DEBIAN-CVE-2025-40195, GHSA-qhqr-659q-mhg7, ROOT-OS-DEBIAN-11-CVE-2025-40195, ROOT-OS-DEBIAN-12-CVE-2025-40195 and 4 more.