# CVE-2025-40022: crypto: af_alg - Fix incorrect boolean values in af_alg_ctx

> Incorrect boolean handling in Linux kernel crypto module may cause logic errors, requiring local access to exploit.

- **Severity:** Not scored
- **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:** 24 Oct 2025
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2025-40022, DEBIAN-CVE-2025-40022, GHSA-rjhr-rr92-fh8c, ROOT-OS-DEBIAN-11-CVE-2025-40022, ROOT-OS-DEBIAN-12-CVE-2025-40022, ROOT-OS-DEBIAN-13-CVE-2025-40022, UBUNTU-CVE-2025-40022

## What is CVE-2025-40022?

CVE-2025-40022 is a vulnerability in Linux, published on 24 Oct 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: af_alg - Fix incorrect boolean values in af_alg_ctx

Commit 1b34cbbf4f01 ("crypto: af_alg - Disallow concurrent writes in
af_alg_sendmsg") changed some fields from bool to 1-bit bitfields of
type u32.

However, some assignments to these fields, specifically 'more' and
'merge', assign values greater than 1.  These relied on C's implicit
conversion to bool, such that zero becomes false and nonzero becomes
true.

With a 1-bit bitfields of type u32 instead, mod 2 of the value is taken
instead, resulting in 0 being assigned in some cases when 1 was intended.

Fix this by restoring the bool type.

## Which versions are affected by CVE-2025-40022?


## How do I fix CVE-2025-40022?

Apply the vendor's patch.

## Is CVE-2025-40022 being exploited?

There is no known exploitation of CVE-2025-40022 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40022 and fix it if it is affected.

What it is: CVE-2025-40022 is a vulnerability in Linux, published on 24 Oct 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-2025-40022 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-2025-40022/ (Markdown: https://insights.sbomify.com/CVE-2025-40022/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40022
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40022
- OSV: https://osv.dev/vulnerability/CVE-2025-40022

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-40022/
Summaries are generated and may contain mistakes; the official description above is the record.