gnark is vulnerable to signature malleability in EdDSA and ECDSA due to missing scalar checks

Vulnerability Description

gnark is a zero-knowledge proof system framework. In versions prior to 0.14.0, the Verify function in eddsa.go and ecdsa.go used the S value from a signature without asserting that 0 ≤ S < order, leading to a signature malleability vulnerability. Because gnark’s native EdDSA and ECDSA circuits lack essential constraints, multiple distinct witnesses can satisfy the same public inputs. In protocols where nullifiers or anti-replay checks are derived from R and S, this enables signature malleability and may allow double spending. This issue has been addressed in version 0.14.0.

References

• https://github.com/Consensys/gnark/security/advisories/GHSA-95v9-hv42-pwrj
• https://github.com/Consensys/gnark/commit/0ba6730f05537a351517998add89a61a0d82716e