Is This vulnerability exploited in the wild?

No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

How severe is This vulnerability?

High severity, with a CVSS score of 8.8, published 4 December 2025.

Which products and versions are affected?

libcrux-intrinsics (crates.io) = 0.0.3; libcrux-ml-dsa (crates.io) = 0.0.3; libcrux-ml-kem (crates.io) = 0.0.3.

Is there a fix for This vulnerability?

A patch was published on 2025-11-03: Fix merged in PR #1222; version 0.0.4 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is This vulnerability attacked?

It is attacked over the network, in a software library.

Check whether you run libcrux-intrinsics (crates.io), libcrux-ml-dsa (crates.io) or libcrux-ml-kem (crates.io) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

libcrux incorrect calculation on aarch64

Severity: high · CVSS 8.8 · Published 2025-12-04

libcrux is a cryptographic library used for quantum-resistant encryption and digital signatures. On certain ARM64 processors, version 0.0.3 contained a calculation error that produced incorrect cryptographic outputs—corrupting encrypted shared secrets and invalidating digital signatures. Applications relying on this library would fail security checks or expose encrypted data to compromise.

Technologies: libcrux-ml-dsa (crates.io). Vendors: crates.io.

Quick answers

Is This vulnerability exploited in the wild?: No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
How severe is This vulnerability?: High severity, with a CVSS score of 8.8, published 4 December 2025.
Which products and versions are affected?: libcrux-intrinsics (crates.io) = 0.0.3; libcrux-ml-dsa (crates.io) = 0.0.3; libcrux-ml-kem (crates.io) = 0.0.3.
Is there a fix for This vulnerability?: A patch was published on 2025-11-03: Fix merged in PR #1222; version 0.0.4 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is This vulnerability attacked?: It is attacked over the network, in a software library.
Am I affected?: Check whether you run libcrux-intrinsics (crates.io), libcrux-ml-dsa (crates.io) or libcrux-ml-kem (crates.io) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability is a cryptographic calculation error (CWE-327) in the ARM64 fallback implementation of the vxarq_u64 intrinsic within libcrux-intrinsics. On aarch64 platforms without native vxarq_u64 support, the fallback function passed incorrect operands to shift operations, producing corrupted results. This affected SHA-3 digest computation and cryptographic sampling in ML-KEM (key encapsulation) and ML-DSA (digital signature) modules, yielding incorrect shared secrets and invalid signatures. The attack is network-accessible with no authentication or user interaction required (CVSS 8.8, vector AV:N/AC:L/AT:N/PR:N/UI:N). The fix was applied in libcrux-intrinsics v0.0.4.

Affected products

cryspen libcrux-intrinsics 0.0.3
cryspen libcrux-ml-kem 0.0.3
cryspen libcrux-ml-dsa 0.0.3

Timeline

2025-12-04: disclosed: Published to GitHub Advisory Database
2025-11-03: patched: Fix merged in PR #1222; version 0.0.4 released

References

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