The Elliptic package 6.5.7 for Node.js, in its for ECDSA implementation, does not correctly verify valid signatures if the hash contains at least four leading 0 bytes and when the order of the elliptic curve's base point is smaller than the hash, because of an _truncateToN anomaly. This leads to valid signatures being rejected. Legitimate transactions or communications may be incorrectly flagged as invalid.
The verify function in lib/elliptic/eddsa/index.js in the Elliptic package before 6.5.6 for Node.js omits "sig.S().gte(sig.eddsa.curve.n) || sig.S().isNeg()" validation.
In the Elliptic package 6.5.6 for Node.js, ECDSA signature malleability occurs because there is a missing check for whether the leading bit of r and s is zero.
In the Elliptic package 6.5.6 for Node.js, EDDSA signature malleability occurs because there is a missing signature length check, and thus zero-valued bytes can be removed or appended.