{"id":"CVE-2021-43570","aliases":["GHSA-r28h-x6hv-2fq3"],"url":"https://o3.security/vulnerability/CVE-2021-43570","summary":"Improper Verification of Cryptographic Signature in starkbank-ecdsa","details":"The verify function in the Stark Bank Java ECDSA library (ecdsa-java) 1.0.0 fails to check that the signature is non-zero, which allows attackers to forge signatures on arbitrary messages.","published":"2021-11-09T22:15:07.640Z","modified":"2026-07-09T05:45:32.969639Z","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":null,"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"Maven","name":"com.starkbank.ellipticcurve:starkbank-ecdsa","fixedVersion":"1.0.1"}],"fix":{"url":"https://github.com/starkbank/ecdsa-java/pull/16","label":"starkbank/ecdsa-java#16"},"references":[{"type":"ADVISORY","url":"https://github.com/starkbank/ecdsa-java/releases/tag/v1.0.1"},{"type":"EVIDENCE","url":"https://research.nccgroup.com/2021/11/08/technical-advisory-arbitrary-signature-forgery-in-stark-bank-ecdsa-libraries/"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-43570"},{"type":"WEB","url":"https://github.com/starkbank/ecdsa-java/pull/16"},{"type":"WEB","url":"https://github.com/starkbank/ecdsa-java/commit/ed22e484186d6c66d3686bfe39d01bdbabf219b6"},{"type":"PACKAGE","url":"https://github.com/starkbank/ecdsa-java"},{"type":"WEB","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":"2026-07-09T05:45:32.969639Z"}}