{"id":"CVE-2021-43571","aliases":["GHSA-q9q6-f556-gpm7"],"url":"https://o3.security/vulnerability/CVE-2021-43571","summary":"Improper Verification of Cryptographic Signature in starkbank-ecdsa","details":"The verify function in the Stark Bank Node.js ECDSA library (ecdsa-node) 1.1.2 fails to check that the signature is non-zero, which allows attackers to forge signatures on arbitrary messages.","published":"2021-11-09T22:15:07.683Z","modified":"2026-07-09T00:22:28.868303Z","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":{"score":0.00994,"percentile":0.5947,"asOf":"2026-08-23"},"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"npm","name":"starkbank-ecdsa","fixedVersion":"1.1.3"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/starkbank/ecdsa-node/releases/tag/v1.1.3"},{"type":"EVIDENCE","url":"https://research.nccgroup.com/2021/11/08/technical-advisory-arbitrary-signature-forgery-in-stark-bank-ecdsa-libraries/"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T00:22:28.868303Z"}}