# CVE-2026-74566: keys: make keyring key-chunk byte order agree with keyring_diff_objects()

> A local attacker can craft key descriptions to cause collisions in the Linux kernel keyring, leading to a denial of service.

- **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:** 15 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** AZL-96093, BELL-CVE-2026-74566, DEBIAN-CVE-2026-74566, GHSA-987h-mx48-c6mp, UBUNTU-CVE-2026-74566

## What is CVE-2026-74566?

CVE-2026-74566 is a denial of service vulnerability in Linux, published on 15 Aug 2026. 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:

keys: make keyring key-chunk byte order agree with keyring_diff_objects()

keyring_get_key_chunk() loads description bytes into the index chunk low
address first, while keyring_diff_objects() numbers the first differing
bit from the low end and folds the absolute byte index into the level
without removing the inline-prefix offset the level already carries.
The two disagree on byte order and bit position, so the array can be
told two keys first differ at a bit that does not differ in the chunk
the walker uses, letting crafted descriptions collide into one node.

Load the chunk in the order keyring_diff_objects() assumes and drop the
inline-prefix length when folding the byte index into the level.  This
only changes the in-memory ordering used to place keys within a keyring;
add, search and read of non-colliding keys are unaffected.

## Which versions are affected by CVE-2026-74566?


## How do I fix CVE-2026-74566?

Apply the vendor's patch.

## Is CVE-2026-74566 being exploited?

There is no known exploitation of CVE-2026-74566 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74566 and fix it if it is affected.

What it is: CVE-2026-74566 is a denial of service vulnerability in Linux, published on 15 Aug 2026. 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-2026-74566 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-2026-74566/ (Markdown: https://insights.sbomify.com/CVE-2026-74566/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74566
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74566
- OSV: https://osv.dev/vulnerability/CVE-2026-74566

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74566/
Summaries are generated and may contain mistakes; the official description above is the record.