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Medium · 5.9 CVE-2026-55174 EUVD-2026-90188

UltrafastSecp256k1: ECDSA adaptor verification accepts non-adaptable pre-signatures due to missing DLEQ binding

Published Sep 30, 2026 · Updated Sep 30, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
shrec UltrafastSecp256k1 < 4.2.0 —

References