python-ecdsa vulnerable to Minerva attack on P-256

Vulnerability Description

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 are vulnerable to the Minerva attack. As of time of publication, no known patched version exists.

References

• https://github.com/tlsfuzzer/python-ecdsa/security/advisories/GHSA-wj6h-64fc-37mp
• https://github.com/tlsfuzzer/python-ecdsa/blob/master/SECURITY.md
• https://minerva.crocs.fi.muni.cz/
• https://securitypitfalls.wordpress.com/2018/08/03/constant-time-compare-in-python/