Elliptic's verify function omits uniqueness validation

The Elliptic package 6.5.5 for Node.js for EDDSA implementation does not perform the required check if the signature proof(s) is within the bounds of the order n of the base point of the elliptic curve, leading to signature malleability. Namely, the verify function in lib/elliptic/eddsa/index.js omits sig.S().gte(sig.eddsa.curve.n) || sig.S().isNeg() validation.

This vulnerability could have a security-relevant impact if an application relies on the uniqueness of a signature.