{"cve":"CVE-2022-31021","nvd":{"published":"2024-01-16T22:15:37.080","modified":"2026-06-17T04:44:37.357","status":"Modified","description":"Ursa is a cryptographic library for use with blockchains. A weakness in the Hyperledger AnonCreds specification that is not mitigated in the Ursa and AnonCreds implementations is that the Issuer does not publish a key correctness proof demonstrating that a generated private key is sufficient to meet the unlinkability guarantees of AnonCreds. The Ursa and AnonCreds CL-Signatures implementations always generate a sufficient private key. A malicious issuer could in theory create a custom CL Signature implementation (derived from the Ursa or AnonCreds CL-Signatures implementations) that uses weakened private keys such that presentations from holders could be shared by verifiers to the issuer who could determine the holder to which the credential was issued. This vulnerability could impact holders of AnonCreds credentials implemented using the CL-signature scheme in the Ursa and AnonCreds implementations of CL Signatures. The ursa project has has moved to end-of-life status and no fix is expected.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","score":5.3},"cwes":["CWE-829"],"references":["https://github.com/hyperledger/ursa/security/advisories/GHSA-2q6j-gqc4-4gw3","https://www.brics.dk/RS/98/29/BRICS-RS-98-29.pdf","https://github.com/hyperledger/ursa/security/advisories/GHSA-2q6j-gqc4-4gw3","https://www.brics.dk/RS/98/29/BRICS-RS-98-29.pdf"],"products":["hyperledger:ursa"],"source":"nvd","synced_at":"2026-10-19T21:44:57.175229480+00:00"},"epss":{"cve":"CVE-2022-31021","score":0.00428,"percentile":0.37077,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-2q6j-gqc4-4gw3","url":"https://osv.dev/vulnerability/GHSA-2q6j-gqc4-4gw3","summary":"Breaking unlinkability in Identity Mixer using malicious keys","modified":"2024-01-19T19:28:13Z","packages":[{"ecosystem":"crates.io","name":"anoncreds-clsignatures","purl":"pkg:cargo/anoncreds-clsignatures","ranges":["all versions"],"fixed":[]},{"ecosystem":"crates.io","name":"ursa","purl":"pkg:cargo/ursa","ranges":["<=0.3.7"],"fixed":[]}]}],"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."]}