CVE-2024-21670 CL-Signatures Revocation Scheme in Ursa has flaws that allow a holder to demonstrate non-revocation of a revoked credential

What is CVE-2024-21670?

CVE-2024-21670 is a medium-severity vulnerability in hyperledger-archives ursa, published on 16 Jan 2024. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

Official 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 A verifier may verify a credential from a holder as being "not revoked" when in fact, the holder's credential has been revoked.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.

Weakness: CWE-327

Which versions are affected by CVE-2024-21670?

4 open source packages ship an affected version, including ursa and anoncreds-clsignatures. It affects 1 product.

Products include Hyperledger Ursa.

How do I fix CVE-2024-21670?

No fix has been published for CVE-2024-21670 yet. Limit exposure of the affected software until one is available.

Is CVE-2024-21670 being exploited?

There is no known exploitation of CVE-2024-21670 in the wild and no public exploit code.

Other vulnerabilities in hyperledger-archives ursa

• CVE-2024-22192 Ursa CL-Signatures Revocation allows verifiers to generate unique identifiers for holders Medium 6.5
• CVE-2022-31021 Unlinkability broken in ursa when verifiers use malicious keys Low 3.3

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-r78f-4q2q-hvv4.