CVE-2025-40036 misc: fastrpc: fix possible map leak in fastrpc_put_args
A local attacker can trigger a memory leak in the Linux kernel's fastrpc driver by causing a copy_to_user failure, leading to resource exhaustion and denial of service.
- 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-2025-40036?
CVE-2025-40036 is a denial of service vulnerability in Linux, published on 28 Oct 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:
misc: fastrpc: fix possible map leak in fastrpc_put_args
copy_to_user() failure would cause an early return without cleaning up the fdlist, which has been updated by the DSP. This could lead to map leak. Fix this by redirecting to a cleanup path on failure, ensuring that all mapped buffers are properly released before returning.
Which versions are affected by CVE-2025-40036?
How do I fix CVE-2025-40036?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-40036 being exploited?
There is no known exploitation of CVE-2025-40036 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-40036, DEBIAN-CVE-2025-40036, GHSA-w4pg-p4j3-82c8, ROOT-OS-DEBIAN-11-CVE-2025-40036, ROOT-OS-DEBIAN-12-CVE-2025-40036, ROOT-OS-DEBIAN-13-CVE-2025-40036 and 3 more.