{"cve":"CVE-2020-12607","nvd":{"published":"2020-06-02T21:15:10.607","modified":"2026-06-17T02:52:00.790","status":"Modified","description":"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^-1, 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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","score":7.5},"cwes":["CWE-347"],"references":["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/issues/52","https://github.com/AntonKueltz/fastecdsa/commit/4a16daeaf139be20654ef58a9fe4c79dc030458c"],"products":["antonkueltz:fastecdsa"],"source":"nvd","synced_at":"2026-10-19T21:05:42.039641217+00:00"},"epss":{"cve":"CVE-2020-12607","score":0.01311,"percentile":0.70663,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-56wv-2wr9-3h9r","url":"https://osv.dev/vulnerability/GHSA-56wv-2wr9-3h9r","summary":"Improper Verification of Cryptographic Signature in fastecdsa","modified":"2025-02-12T18:54:35.292885Z","packages":[{"ecosystem":"PyPI","name":"fastecdsa","purl":"pkg:pypi/fastecdsa","ranges":["<2.1.2"],"fixed":["2.1.2"]}]},{"id":"PYSEC-2020-42","url":"https://osv.dev/vulnerability/PYSEC-2020-42","summary":"","modified":"2023-11-08T04:02:10.552763Z","packages":[{"ecosystem":"PyPI","name":"fastecdsa","purl":"pkg:pypi/fastecdsa","ranges":["<2.1.2"],"fixed":["2.1.2"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}