The bsv-rs library's Signature::from_der function leniently parses DER-encoded ECDSA signatures, allowing signatures with extra trailing bytes, incorrect sequence lengths, or unnecessary leading zeros in R or S values. This leniency causes multiple distinct byte strings to verify as the same signature over the same data, potentially impacting applications that compare, hash, or store signature bytes. The issue is fixed in versions 0.8.6 and 0.9.0-beta.7.0, which reject these malformed signatures. However, signature byte uniqueness is not fully guaranteed due to the nature of ECDSA's low-S normalization.