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GHSA-435g-fcv3-8j26 libcrux-ecdh

Fix: cryspen/libcrux#1301

GHSA-435g-fcv3-8j26 is a CWE-347 vulnerability in libcrux-ecdh. A fix is available for libcrux-ecdh — see the affected versions and patch details below.

Bug-Fixes in `libcrux-ecdh`, `libcrux-ed25519`, `libcrux-psq`

Also known asCVE-2026-76234RUSTSEC-2026-0023RUSTSEC-2026-0024RUSTSEC-2026-0025RUSTSEC-2026-0026
Published
Feb 12, 2026
Updated
Aug 20, 2026
Affected
3 pkgs
Patched
3 / 3
Exploits
None indexed
Exploitation data as of Sep 18, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-435g-fcv3-8j26.

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs13th percentile — riskier than 13% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

3 pkgs affected
🦀libcrux-ecdh🦀libcrux-ed25519🦀libcrux-psq

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

In accordance with our security policy for libcrux, we publish a GitHub security advisory for any releases whose CHANGELOG includes bug-fixes, and encourage our users to upgrade. The latest releases of the libcrux-ecdh, libcrux-ed25519 and libcrux-psq crates contain the following bug-fixes:

libcrux-ecdh

  • #1301: Check length and clamping in X25519 secret validation. This is a breaking change since errors are now raised on unclamped X25519 secrets or inputs of the wrong length

libcrux-ed25519

  • #1320: Remove duplicated clamping step during key generation

The issue fixed in #1320 was first reported by Nadim Kobeissi.

libcrux-psq

  • #1319: Propagate AEADError instead of panicking
  • #1301: Fix broken clamping check for imported X25519 secret keys

The issue fixed in #1319 was first reported by Nadim Kobeissi.

Affected Packages

3 total 3 fixed
EcosystemPackageVulnerable rangeFix
🦀crates.iolibcrux-ecdhall versions0.0.6cargo update -p libcrux-ecdh --precise 0.0.6
🦀crates.iolibcrux-ed25519all versions0.0.6cargo update -p libcrux-ed25519 --precise 0.0.6
🦀crates.iolibcrux-psqall versions0.0.7cargo update -p libcrux-psq --precise 0.0.7

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-ecdh, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update libcrux-ecdh to 0.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-435g-fcv3-8j26 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-435g-fcv3-8j26 can be triaged on real exposure rather than presence alone.

Tailored to GHSA-435g-fcv3-8j26. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

In accordance with our [security policy for `libcrux`](https://github.com/cryspen/libcrux/blob/main/SECURITY.md), we publish a GitHub security advisory for any releases whose CHANGELOG includes bug-fixes, and encourage our users to upgrade. The latest releases of the `libcrux-ecdh`, `libcrux-ed25519` and `libcrux-psq` crates contain the following bug-fixes: ## `libcrux-ecdh` - [#1301](https://github.com/cryspen/libcrux/pull/1301): Check length and clamping in X25519 secret validation. This is a breaking change since errors are now raised on unclamped X25519 secrets or inputs of the wrong len
O3 Security · Impact-Aware SCA

Is GHSA-435g-fcv3-8j26 in your dependencies?

O3 Security finds GHSA-435g-fcv3-8j26 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-435g-fcv3-8j26: libcrux-ecdh | O3 Security