CVE-2025-40182: crypto: skcipher - Fix reqsize handling

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-11-12 · updated 2026-10-19

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/aCL8BxpHr5OpT04k@gondor.apana.org.au/ [2]: https://gist.github.com/Pratham-T/24247446f1faf4b7843e4014d5089f6b

Affected products

Linux kernel: 6.16 — fixed in 6.18

How to fix

Upgrade to a fixed version: Linux kernel 6.18. Check the vendor advisory for mitigations.

References

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