Credential-holder identification via unverifiable issuer keys
Published Jan 16, 2024 · Updated Jun 2, 2025
Cryptographic design weakness in Hyperledger Ursa 0.3.7 and earlier allows context-dependent attackers to identify credential holders. The CL-signature issuer key proof does not establish that p and q are distinct, same-sized safe primes, so a custom issuer can deliberately use a weak key. Exploitation requires a malicious issuer and colluding verifiers to share holder presentations, enabling brute-force correlation without altering credentials.
Summary
What happened
Cryptographic design weakness in Hyperledger Ursa 0.3.7 and earlier allows context-dependent attackers to identify credential holders. The CL-signature issuer key proof does not establish that p and q are distinct, same-sized safe primes, so a custom issuer can deliberately use a weak key. Exploitation requires a malicious issuer and colluding verifiers to share holder presentations, enabling brute-force correlation without altering credentials.
The record
- CVE
- CVE-2022-31021
- Published
- Jan 16, 2024
- Updated
- Jun 2, 2025
- Vendor
- Hyperledger Foundation
- Product
- Hyperledger Ursa
- Classifications
- CWE-829
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 16, 2024CVE publishedPublication date reported by the CVE source.
- Jun 2, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=<= 0.3.7
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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