CVE-2025-38049 x86/resctrl: Fix allocation of cleanest CLOSID on platforms with no monitors
A NULL pointer dereference in the Linux kernel x86/resctrl subsystem can cause a denial of service when creating control groups on platforms without cache occupancy monitors.
- 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-2025-38049?
CVE-2025-38049 is a medium-severity vulnerability in Linux kernel, published on 18 Apr 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:
x86/resctrl: Fix allocation of cleanest CLOSID on platforms with no monitors
Commit
6eac36bb9eb0 ("x86/resctrl: Allocate the cleanest CLOSID by searching closid_num_dirty_rmid")
added logic that causes resctrl to search for the CLOSID with the fewest dirty cache lines when creating a new control group, if requested by the arch code. This depends on the values read from the llc_occupancy counters. The logic is applicable to architectures where the CLOSID effectively forms part of the monitoring identifier and so do not allow complete freedom to choose an unused monitoring identifier for a given CLOSID.
This support missed that some platforms may not have these counters. This causes a NULL pointer dereference when creating a new control group as the array was not allocated by dom_data_init().
As this feature isn't necessary on platforms that don't have cache occupancy monitors, add this to the check that occurs when a new control group is allocated.
Weakness: CWE-476
Which versions are affected by CVE-2025-38049?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-38049?
Apply the vendor's patch.
Is CVE-2025-38049 being exploited?
There is no known exploitation of CVE-2025-38049 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-38049, DEBIAN-CVE-2025-38049, GHSA-3f85-ch4h-849r, UBUNTU-CVE-2025-38049.