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GHSA-2cgv-28vr-rv6j — libcrux-intrinsics

Fix: cryspen/libcrux#1222

GHSA-2cgv-28vr-rv6j is a security vulnerability in libcrux-intrinsics. A fix is available for libcrux-intrinsics — see the affected versions and patch details below.

libcrux incorrectly calculates on aarch64

Also known asRUSTSEC-2025-0133
Published
Dec 4, 2025
Updated
Feb 22, 2026
Affected
3 pkgs
Patched
3 / 3
Exploits
None indexed
Exploitation data as of Feb 22, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

3 pkgs affected
🦀libcrux-intrinsics🦀libcrux-ml-kem🦀libcrux-ml-dsa

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

On platforms without the core::arch::aarch64::vxarq_u64 intrinsic, an unverified fallback in libcrux-intrinsics v0.0.3 passed incorrect arguments and produced wrong results. This corrupted SHA-3 digests and caused libcrux-ml-kem and libcrux-ml-dsa to sample incorrectly, yielding incorrect shared secrets and invalid signatures.

The issue has been fixed in v0.0.4.

Affected Packages

3 total 3 fixed
EcosystemPackageVulnerable rangeFix
🦀crates.iolibcrux-intrinsics≥ 0.0.3&&< 0.0.40.0.4cargo update -p libcrux-intrinsics --precise 0.0.4
🦀crates.iolibcrux-ml-kem≥ 0.0.3&&< 0.0.40.0.4cargo update -p libcrux-ml-kem --precise 0.0.4
🦀crates.iolibcrux-ml-dsa≥ 0.0.3&&< 0.0.40.0.4cargo update -p libcrux-ml-dsa --precise 0.0.4

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for libcrux-intrinsics, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update libcrux-intrinsics to 0.0.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2cgv-28vr-rv6j is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-2cgv-28vr-rv6j can be triaged on real exposure rather than presence alone.

Tailored to GHSA-2cgv-28vr-rv6j. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

On platforms without the `core::arch::aarch64::vxarq_u64` intrinsic, an unverified fallback in `libcrux-intrinsics` v0.0.3 passed incorrect arguments and produced wrong results. This corrupted SHA-3 digests and caused `libcrux-ml-kem` and `libcrux-ml-dsa` to sample incorrectly, yielding incorrect shared secrets and invalid signatures. The issue has been fixed in v0.0.4.
O3 Security · Impact-Aware SCA

Is GHSA-2cgv-28vr-rv6j in your dependencies?

O3 Security finds GHSA-2cgv-28vr-rv6j across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-2cgv-28vr-rv6j: libcrux-intrinsics | O3 Security