cggmp21 has a missing check in the ZK proof used in CGGMP21

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

9.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2025-66016: 0.20% estimated exploitation activity in the next 30 days; percentile 9.84 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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. Patches cggmp21 v0.6.3 is a patch release that contains a fix that introduces this specific missing check However, cggmp21 recommends upgrading to cggmp24 v0.7.0-alpha.2 which contains many other security checks as a precaution. Follow migration guideline to upgrade. 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.

Published by the source

25 Nov 2025, 20:41 UTC

Last modified by the source

27 Nov 2025, 08:59 UTC

Source last checked

26 Oct 2026, 15:39 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-m95p-425x-x889

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# Patch Next advisory brief: CVE-2025-66016

Advisory: cggmp21 has a missing check in the ZK proof used in CGGMP21
IDs: CVE-2025-66016, GHSA-m95p-425x-x889
Record: https://patchnext.com/advisories/cve-2025-66016 (revision 1, source checked 26 Oct 2026, 15:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: cggmp24 0.7.0-alpha.2; cggmp21 0.6.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io cggmp24: affected < 0.7.0-alpha.2; fixed in 0.7.0-alpha.2
- crates.io cggmp21: affected < 0.6.3; fixed in 0.6.3

## Suggested inspection (read-only)
- crates.io cggmp24: check the installed version with your package manager.
- crates.io cggmp21: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on cggmp24, cggmp21.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-m95p-425x-x889 (GitHub-reviewed advisory GHSA-m95p-425x-x889 lists affected ranges: crates.io cggmp21 >=0 =0 <0.7.0-alpha.2)

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