CVE-2025-22040 ksmbd: fix session use-after-free in multichannel connection
A race condition in the Linux kernel ksmbd module allows a use-after-free, potentially enabling local attackers to execute code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-22040?
CVE-2025-22040 is a high-severity use after free vulnerability in Debian Debian Linux, published on 16 Apr 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix session use-after-free in multichannel connection
There is a race condition between session setup and ksmbd_sessions_deregister. The session can be freed before the connection is added to channel list of session. This patch check reference count of session before freeing it.
Weakness: CWE-416
Which versions are affected by CVE-2025-22040?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-22040?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2025-22040 being exploited?
There is no known exploitation of CVE-2025-22040 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2025-22040, DEBIAN-CVE-2025-22040, GHSA-q9qg-fj9x-mqhg, ROOT-OS-UBUNTU-2204-CVE-2025-22040, ROOT-OS-UBUNTU-2404-CVE-2025-22040, UBUNTU-CVE-2025-22040.