Summary
cggmp21 has a missing check in the ZK proof used in CGGMP21
Workarounds
Update to cggmp21 v0.6.3, a minor release that contains a minimal security patch.
However, for full mitigation, users will need to upgrade to cggmp24 v0.7.0-alpha.2 as it contains many more security check implementations.
Resources
Read this blog post to learn more.
Impact
cggmp21 concerns a missing check in the ZK proof that enables an attack in which a single malicious signer can reconstruct full private key.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
cggmp21 v0.6.3is a patch release that contains a fix that introduces this specific missing check- However, cggmp21 recommends upgrading to
cggmp24 v0.7.0-alpha.2which contains many other security checks as a precaution. Follow migration guideline to upgrade.
Frequently Asked Questions
- What is CVE-2025-66016? CVE-2025-66016 is a critical-severity security vulnerability in cggmp21 (rust), affecting versions < 0.6.3. It is fixed in 0.6.3, 0.7.0-alpha.2.
- Which packages are affected by CVE-2025-66016?
cggmp21(rust) (versions < 0.6.3)cggmp24(rust) (versions < 0.7.0-alpha.2)
- Is there a fix for CVE-2025-66016? Yes. CVE-2025-66016 is fixed in 0.6.3, 0.7.0-alpha.2. Upgrade to this version or later.
- Is CVE-2025-66016 exploitable, and should I be worried? Whether CVE-2025-66016 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-66016 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2025-66016?
- Upgrade
cggmp21to 0.6.3 or later - Upgrade
cggmp24to 0.7.0-alpha.2 or later
- Upgrade