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

### 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](https://github.com/LFDT-Lockness/cggmp21/blob/v0.7.0-alpha.2/CGGMP21_MIGRATION.md) 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](https://www.dfns.co/article/cggmp21-vulnerabilities-patched-and-explained) to learn more.

Source published

25 Nov 2025 20:41:04 UTC

Source modified

27 Nov 2025 09:16:27 UTC

Observed here

24 Oct 2026 13:19:54 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · 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

Publisher rating · CRITICAL