# RUSTSEC-2026-0161: `pqcrypto-mlkem` is unmaintained: upstream PQClean project being archived

> The pqcrypto-mlkem crate is unmaintained due to upstream archiving, requiring users to migrate to the ml-kem crate for continued security support.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not stated
- **Attackable:** Not stated
- **Victim action needed:** Not stated
- **Fix available:** No
- **Published:** 4 Jun 2026

## What is RUSTSEC-2026-0161?

RUSTSEC-2026-0161 is a vulnerability in pqcrypto-mlkem, published on 4 Jun 2026. 

### Official description

This crate provides Rust bindings to ML-KEM (FIPS 203) via C implementations
from [PQClean](https://github.com/PQClean/PQClean). The PQClean project is
being archived in or after July 2026 (see [PQClean/PQClean#604](https://github.com/PQClean/PQClean/issues/604)),
after which no further security patches or bug fixes will be applied to the
upstream implementations.

As a result, this crate will no longer receive updates. Users should migrate
to the [`ml-kem`](https://crates.io/crates/ml-kem) crate, which provides a
pure-Rust implementation of ML-KEM (FIPS 203).

## Which versions are affected by RUSTSEC-2026-0161?

1 open source package ship an affected version, including pqcrypto-mlkem.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `pqcrypto-mlkem` | crates.io | From 0.0.0-0 | None |

## How do I fix RUSTSEC-2026-0161?

No fix has been published for RUSTSEC-2026-0161 yet. Limit exposure of the affected software until one is available.

## Is RUSTSEC-2026-0161 being exploited?

There is no known exploitation of RUSTSEC-2026-0161 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2026-0161 and fix it if it is affected.

What it is: RUSTSEC-2026-0161 is a vulnerability in pqcrypto-mlkem, published on 4 Jun 2026. 
Exploitation: There is no known exploitation of RUSTSEC-2026-0161 in the wild and no public exploit code.

Affected packages and fixed versions:
- pqcrypto-mlkem (crates.io): affected from 0.0.0-0; no fix listed

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/RUSTSEC-2026-0161/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0161/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2026-0161

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2026-0161/
Summaries are generated and may contain mistakes; the official description above is the record.