{"id":"CVE-2021-43570","aliases":["EUVD-2021-2385","GHSA-r28h-x6hv-2fq3"],"status":"published","title":"Improper Verification of Cryptographic Signature in starkbank-ecdsa","description":"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.","severity":{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.01027,"percentile":0.63857,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-347"],"published":"2021-11-09T21:05:46Z","modified":"2026-10-20T10:54:08Z","fixes":[{"ecosystem":"Maven","package":"com.starkbank.ellipticcurve:starkbank-ecdsa","fixed_in":["1.0.1"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Maven","package":"com.starkbank.ellipticcurve:starkbank-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.0.1"}]}]},{"source":"osv","ecosystem":"Maven","package":"com.starkbank.ellipticcurve:starkbank-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.0.1"}]}],"versions":["1.0.0"]}],"products":[{"vendor":"starkbank","product":"ecdsa-java"}],"references":[{"url":"https://research.nccgroup.com/2021/11/08/technical-advisory-arbitrary-signature-forgery-in-stark-bank-ecdsa-libraries/","tags":["x_refsource_MISC","x_transferred","Exploit","Third Party Advisory","evidence"]},{"url":"https://github.com/starkbank/ecdsa-java/releases/tag/v1.0.1","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-43570","tags":["advisory"]},{"url":"https://github.com/starkbank/ecdsa-java/pull/16","tags":["web"]},{"url":"https://github.com/starkbank/ecdsa-java/commit/ed22e484186d6c66d3686bfe39d01bdbabf219b6","tags":["web"]},{"url":"https://research.nccgroup.com/2021/11/08/technical-advisory-arbitrary-signature-forgery-in-stark-bank-ecdsa-libraries","tags":["web"]},{"url":"https://github.com/advisories/GHSA-r28h-x6hv-2fq3"},{"url":"https://github.com/starkbank/ecdsa-java","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2021-43570","description":"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.","status":"published","published":"2021-11-09T21:05:46Z","modified":"2024-08-04T04:03:07.993Z","updated_at":"2026-11-02T14:32:57.033395Z"}],"euvd":[{"id":"EUVD-2021-2385","description":"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.","status":"published","published":"2021-11-09T21:05:46Z","modified":"2024-08-04T04:03:07Z","updated_at":"2026-11-03T03:24:13.772922Z"}],"ghsa":[{"id":"GHSA-r28h-x6hv-2fq3","title":"Improper Verification of Cryptographic Signature in starkbank-ecdsa","description":"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.","status":"published","published":"2021-11-10T20:48:00Z","modified":"2025-01-20T16:11:31Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T14:38:27.974809Z"}],"nvd":[{"id":"CVE-2021-43570","description":"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.","status":"published","published":"2021-11-09T22:15:07.64Z","modified":"2026-06-17T04:11:09.253Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":7.5,"vector":"AV:N/AC:L/Au:N/C:P/I:P/A:P","level":"high","assessor":"primary"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T14:07:00.984108Z"}],"osv":[{"id":"CVE-2021-43570","description":"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.","status":"published","published":"2021-11-09T22:15:07.64Z","modified":"2026-10-20T10:54:08.772091702Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:44:21.877444Z"},{"id":"GHSA-r28h-x6hv-2fq3","title":"Improper Verification of Cryptographic Signature in starkbank-ecdsa","description":"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.","status":"published","published":"2021-11-10T20:48:00Z","modified":"2025-01-20T16:50:24.558931Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T15:46:55.122811Z"}]}}