The ecdsa PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Versions 0.18.0 and prior is vulnerable to the Minerva attack. As of time of publication, no known patched version exists.
A flaw was found in all python-ecdsa versions before 0.13.3, where it did not correctly verify whether signatures used DER encoding. Without this verification, a malformed signature could be accepted, making the signature malleable. Without proper verification, an attacker could use a malleable signature to create false transactions.
An error-handling flaw was found in python-ecdsa. During signature decoding, malformed DER signatures could raise unexpected exceptions (or no exceptions at all), which could lead to a denial of service.