GHSA-56wv-2wr9-3h9r
Improper Verification of Cryptographic Signature in fastecdsa
Packages
Details
As written in the advisory (Markdown source, shown as plain text).
An issue was discovered in fastecdsa before 2.1.2. When using the NIST P-256 curve in the ECDSA implementation, the point at infinity is mishandled. This means that for an extreme value in k and s<sup>-1</sup>, the signature verification fails even if the signature is correct. This behavior is not solely a usability problem. There are some threat models where an attacker can benefit by successfully guessing users for whom signature verification will fail.
References
External links from the advisory. They lead to third-party sites.
- https://nvd.nist.gov/vuln/detail/CVE-2020-12607
- https://github.com/AntonKueltz/fastecdsa/issues/52
- https://github.com/AntonKueltz/fastecdsa/commit/4a16daeaf139be20654ef58a9fe4c79dc030458c
- https://github.com/AntonKueltz/fastecdsa/commit/7b64e3efaa806b4daaf73bb5172af3581812f8de
- https://github.com/AntonKueltz/fastecdsa/commit/e592f106edd5acf6dacedfab2ad16fe6c735c9d1
- https://github.com/AntonKueltz/fastecdsa
- https://github.com/advisories/GHSA-56wv-2wr9-3h9r
- https://github.com/pypa/advisory-database/tree/main/vulns/fastecdsa/PYSEC-2020-42.yaml