CVE-2025-40182 crypto: skcipher - Fix reqsize handling
A memory corruption vulnerability in the Linux kernel's skcipher crypto API can cause crashes or potentially allow code execution due to improper request size handling.
- 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-2025-40182?
CVE-2025-40182 is a high-severity memory corruption vulnerability in Linux, published on 12 Nov 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:
crypto: skcipher - Fix reqsize handling
Commit afddce13ce81d ("crypto: api - Add reqsize to crypto_alg") introduced cra_reqsize field in crypto_alg struct to replace type specific reqsize fields. It looks like this was introduced specifically for ahash and acomp from the commit description as subsequent commits add necessary changes in these alg frameworks.
However, this is being recommended for use in all crypto algs [1] instead of setting reqsize using crypto_*_set_reqsize(). Using cra_reqsize in skcipher algorithms, hence, causes memory corruptions and crashes as the underlying functions in the algorithm framework have not been updated to set the reqsize properly from cra_reqsize. [2]
Add proper set_reqsize calls in the skcipher init function to properly initialize reqsize for these algorithms in the framework.
[1]: https://lore.kernel.org/linux-crypto/[email protected]/ [2]: https://gist.github.com/Pratham-T/24247446f1faf4b7843e4014d5089f6b
Which versions are affected by CVE-2025-40182?
How do I fix CVE-2025-40182?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-40182 being exploited?
There is no known exploitation of CVE-2025-40182 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-40182, DEBIAN-CVE-2025-40182, GHSA-fxwg-47f2-r9jw, UBUNTU-CVE-2025-40182.