Improper Verification of Cryptographic Signature in starkbank-ecdsa

CRITICAL 9.8CVE-2021-43569 · GHSA-j3jw-j2j8-2wv9 · Published 09/11/2021 · updated 17/06/2026

In short

CVE-2021-43569 is a CRITICAL (CVSS 9.8) vulnerability affecting starkbank-ecdsa, ecdsa-dotnet (starkbank).
Chance of exploitation in the next 30 days (EPSS): 1.1%, higher than 64.6% of all vulnerabilities.
Fix: update to 1.3.2 or later.

Package	Affected versions	Patched versions
starkbank-ecdsa NuGet	`< 1.3.2`	`1.3.2`
ecdsa-dotnet starkbank	`= 1.3.2`	No fix yet

Description

The verify function in the Stark Bank .NET ECDSA library (ecdsa-dotnet) 1.3.1 fails to check that the signature is non-zero, which allows attackers to forge signatures on arbitrary messages.

NVD description

The verify function in the Stark Bank .NET ECDSA library (ecdsa-dotnet) 1.3.1 fails to check that the signature is non-zero, which allows attackers to forge signatures on arbitrary messages.

References

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