# RUSTSEC-2026-0126: AVX2 Implementation Did Not Fully Reduce Intermediate Values

> An incomplete reduction in the AVX2 implementation of ML-DSA can cause panics, potentially leading to denial of service in applications using the library.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Apr 2026

## What is RUSTSEC-2026-0126?

RUSTSEC-2026-0126 is a denial of service vulnerability in libcrux-ml-dsa, published on 27 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The AVX2 implementation of ML-DSA did not fully reduce intermediate
inputs to the inverse NTT, which leads to a testable difference in
panic behaviour of internal functions compared to the portable
implementation.

## Impact
We are not aware of inputs to the public key generation, signing or
verification APIs that trigger a panic in the AVX2 implementation
because the intermediate values were not fully reduced.

## Mitigation
From version `0.0.9` intermediate values on AVX2 platforms are fully
reduced in alignment with the portable implementation.

## Which versions are affected by RUSTSEC-2026-0126?

1 open source package ship an affected version, including libcrux-ml-dsa.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libcrux-ml-dsa` | crates.io | From 0.0.0-0 | 0.0.9 |

## How do I fix RUSTSEC-2026-0126?

Upgrade libcrux-ml-dsa to 0.0.9 or later.

## Is RUSTSEC-2026-0126 being exploited?

There is no known exploitation of RUSTSEC-2026-0126 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2026-0126 and fix it if it is affected.

What it is: RUSTSEC-2026-0126 is a denial of service vulnerability in libcrux-ml-dsa, published on 27 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of RUSTSEC-2026-0126 in the wild and no public exploit code.

Affected packages and fixed versions:
- libcrux-ml-dsa (crates.io): affected from 0.0.0-0; fixed in 0.0.9

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-2026-0126/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0126/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2026-0126

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2026-0126/
Summaries are generated and may contain mistakes; the official description above is the record.