{"cve":"CVE-2024-21670","nvd":{"published":"2024-01-16T22:15:45.810","modified":"2026-06-17T07:09:57.713","status":"Modified","description":"Ursa is a cryptographic library for use with blockchains. The revocation schema that is part of the Ursa CL-Signatures implementations has a flaw that could impact the privacy guarantees defined by the AnonCreds verifiable credential model, allowing a malicious holder of a revoked credential to generate a valid Non-Revocation Proof for that credential as part of an AnonCreds presentation. A verifier may verify a credential from a holder as being \"not revoked\" when in fact, the holder's credential has been revoked. Ursa 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:H/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.1},"cwes":["CWE-327"],"references":["https://github.com/hyperledger-archives/ursa/security/advisories/GHSA-r78f-4q2q-hvv4","https://github.com/hyperledger-archives/ursa/security/advisories/GHSA-r78f-4q2q-hvv4"],"products":["hyperledger:ursa"],"source":"nvd","synced_at":"2026-10-19T21:44:57.175229480+00:00"},"epss":{"cve":"CVE-2024-21670","score":0.00276,"percentile":0.20108,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-r78f-4q2q-hvv4","url":"https://osv.dev/vulnerability/GHSA-r78f-4q2q-hvv4","summary":"CL-Signatures Revocation Scheme in Ursa has flaws that allow a holder to demonstrate non-revocation of a revoked credential","modified":"2026-09-10T03:50:05.091750349Z","packages":[{"ecosystem":"crates.io","name":"ursa","purl":"pkg:cargo/ursa","ranges":["<=0.3.7"],"fixed":[]},{"ecosystem":"crates.io","name":"anoncreds-clsignatures","purl":"pkg:cargo/anoncreds-clsignatures","ranges":["all versions"],"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."]}