CVE-2025-40228 mm/damon/sysfs: catch commit test ctx alloc failure
A missing allocation check in the Linux kernel DAMON sysfs interface can lead to invalid memory access and system crash.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-40228?
CVE-2025-40228 is a vulnerability in Linux, published on 4 Dec 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:
mm/damon/sysfs: catch commit test ctx alloc failure
Patch series "mm/damon/sysfs: fix commit test damon_ctx [de]allocation".
DAMON sysfs interface dynamically allocates and uses a damon_ctx object for testing if given inputs for online DAMON parameters update is valid. The object is being used without an allocation failure check, and leaked when the test succeeds. Fix the two bugs.
This patch (of 2):
The damon_ctx for testing online DAMON parameters commit inputs is used without its allocation failure check. This could result in an invalid memory access. Fix it by directly returning an error when the allocation failed.
Which versions are affected by CVE-2025-40228?
How do I fix CVE-2025-40228?
Apply the vendor's patch.
Is CVE-2025-40228 being exploited?
There is no known exploitation of CVE-2025-40228 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-40228, DEBIAN-CVE-2025-40228, GHSA-2g63-4p26-m2f6, UBUNTU-CVE-2025-40228.