CVE-2025-40217 pidfs: validate extensible ioctls
A local attacker can exploit insufficient validation in Linux kernel pidfs ioctls to potentially escalate privileges or execute code.
- 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-2025-40217?
CVE-2025-40217 is a missing authorization 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:
pidfs: validate extensible ioctls
Validate extensible ioctls stricter than we do now.
Which versions are affected by CVE-2025-40217?
How do I fix CVE-2025-40217?
Apply the vendor's patch.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2025-40217 being exploited?
There is no known exploitation of CVE-2025-40217 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-40217, DEBIAN-CVE-2025-40217, ECHO-85ac-fb53-c7c8, GHSA-qp94-hxp8-gm8p, ROOT-OS-DEBIAN-13-CVE-2025-40217, ROOT-OS-UBUNTU-2204-CVE-2025-40217 and 2 more.