[ CVE-2026-55174 · Published 30 Sep 2026 ]
Vulnerability in shrec UltrafastSecp256k1
CVSS 5.9
EPSS <1%No fix listed yet
[ Why it matters ]Priority signals
- Public proof-of-concept exploit exists (CISA SSVC)
[ Description ]Official description
UltrafastSecp256k1 is a high-performance, multi-backend secp256k1 engine with reproducible audit evidence, compatibility shims, and profile-based review scopes. Prior to version 4.2.0, UltrafastSecp256k1's ECDSA adaptor pre-signature verification accepts forged adaptor pre-signatures whose "r" value is not cryptographically bound to the adaptor point "T". This issue has been patched in version 4.2.0.
[ Fixes ]Fixes and patches
No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.