libcrux-ecdh: Improper Verification of Cryptographic Signature
CVE-2026-76234 is a high-severity improper verification of cryptographic signature vulnerability in libcrux-ecdh from Celabshq, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 0.0.6 as the first without the flaw, so updating libcrux-ecdh to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.31% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update libcrux-ecdh to 0.0.6 or a later version.
- Update libcrux-ed25519 to 0.0.6 or a later version.
- Update libcrux-psq to 0.0.7 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Celabshq | libcrux-ecdh | before 0.0.6 | 0.0.6 |
| Celabshq | libcrux-ed25519 | before 0.0.6 | 0.0.6 |
| Celabshq | libcrux-psq | before 0.0.7 | 0.0.7 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA (vulncheck.com) |
| CVSS 3.1 | 7.5 | High | CNA (vulncheck.com) |
Official description
libcrux-ecdh and libcrux-ed25519 before 0.0.6, and libcrux-psq before 0.0.7, contain cryptographic implementation bugs. libcrux-ecdh did not properly check length and clamping during X25519 secret validation (and had a broken clamping check for imported X25519 secret keys); libcrux-ed25519 performed a duplicated clamping step during key generation; and libcrux-psq panicked instead of propagating an AEADError. These were fixed in the respective patched releases.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Verification of Cryptographic Signature
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
More Improper Verification of Cryptographic Signature vulnerabilities (CWE-347)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Recent Improper Verification of Cryptographic Signature vulnerabilities
- 9.8 Critical severity
- 7.5 High severity
- 8.1 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 8.1 High severity
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