CVE-2022-41340: secp256k1-js implements ECDSA without required r and s validation, leading to signature forgery

The core vulnerability stems from missing cryptographic parameter validation in ECDSA operations. The patch added critical checks in three key functions: 1) ecverify() now explicitly checks for r/s=0 (CVE's primary focus), 2) ecrecover() added r/s=0 validation and recId range checking, and 3) ecsign() added d/z=0 validation. The high confidence for ecverify/ecrecover comes from direct correlation with CWE-347 and the attack vector described - signature forgery through invalid zero-value signatures. The medium confidence for ecsign reflects that while missing d/z validation could enable other attacks, it wasn't the primary signature forgery path described in the advisory.