# 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.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 12 Nov 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-40182, DEBIAN-CVE-2025-40182, GHSA-fxwg-47f2-r9jw, UBUNTU-CVE-2025-40182

## 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/aCL8BxpHr5OpT04k@gondor.apana.org.au/
[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.

## Is CVE-2025-40182 being exploited?

There is no known exploitation of CVE-2025-40182 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40182 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2025-40182 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-40182/ (Markdown: https://insights.sbomify.com/CVE-2025-40182/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40182
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40182
- OSV: https://osv.dev/vulnerability/CVE-2025-40182

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-40182/
Summaries are generated and may contain mistakes; the official description above is the record.