{"id":"CVE-2021-43569","details":"The verify function in the Stark Bank .NET ECDSA library (ecdsa-dotnet) 1.3.1 fails to check that the signature is non-zero, which allows attackers to forge signatures on arbitrary messages.","aliases":["GHSA-j3jw-j2j8-2wv9"],"modified":"2026-07-09T05:45:33.583544Z","published":"2021-11-09T22:15:07.597Z","references":[{"type":"ADVISORY","url":"https://github.com/starkbank/ecdsa-dotnet/releases/tag/v1.3.2"},{"type":"EVIDENCE","url":"https://research.nccgroup.com/2021/11/08/technical-advisory-arbitrary-signature-forgery-in-stark-bank-ecdsa-libraries/"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/starkbank/ecdsa-dotnet","events":[{"introduced":"76b1faf93152c7b0614a2e90ffb2ef51b30606a2"},{"last_affected":"76b1faf93152c7b0614a2e90ffb2ef51b30606a2"},{"fixed":"76b1faf93152c7b0614a2e90ffb2ef51b30606a2"}],"database_specific":{"source":["CPE_STRING","REFERENCES"],"cpe":"cpe:2.3:a:starkbank:ecdsa-dotnet:1.3.2:*:*:*:*:*:*:*","extracted_events":[{"introduced":"1.3.2"},{"last_affected":"1.3.2"}]}}],"versions":["1.3.2","v1.3.2"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-43569.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}