Ursa is a cryptographic library for use with blockchains. The revocation scheme 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. Notably, a malicious verifier may be able to generate a unique identifier for a holder providing a verifiable presentation that includes a Non-Revocation proof. The impact of the flaw is that a malicious verifier may be able to determine a unique identifier for a holder presenting a Non-Revocation proof. Ursa has moved to end-of-life status and no fix is expected.

GitHub, Inc. AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

GitHub, Inc. CWE-327

GitHub, Inc. https://github.com/hyperledger-archives/ursa/security/advisories/GHSA-6698-mhxx-r84g [No types assigned]