CVE-2023-44273

Workarounds

Users can manually validate the inputs to be in corresponding ranges when using serialized signatures (or digests of them) as unique keys.

To address the denial-of-service, the users can install hook to recover panics and recover

Resources

• Verichains advisory for signature malleability.
• Fix https://github.com/Consensys/gnark-crypto/pull/449
• Go blog post "Defer, Panic, and Recover"
• gnark v0.12.0

Acknowledgement

Lack of range checks leading to signature malleability was reported by Verichains.

During deserialization of ECDSA and EdDSA signatures gnark-crypto did not check that the values are in the range [1, n-1] with n being the corresponding modulus (either base field modulus in case of R in EdDSA, and scalar field modulus in case of s,r in ECDSA and s in EdDSA). As this also allowed zero inputs, then it was possible to craft a signature which lead to null pointer dereference, leading to denial-of-service of an application. This also enabled weak signature malleability when the users assumed uniqueness of the serialized signatures (but not the underlying modulo reduced values).

We are not aware of any users impacted by the bug. The implemented signature schemes in gnark-crypto complement the in-circuit versions in gnark, allowing to have end-to-end tests.

CVE-2023-44273 has a CVSS score of 5.1 (Medium). The vector is requires local access, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.12.0); upgrading removes the vulnerable code path.

Kodem intelligence

The issue was patched in PR #449. The fix returns an error during deserialization if the values do not belong to the ranges [1, n-1].

The fix is included in release v0.12.0 and upwards.

1. What is CVE-2023-44273? CVE-2023-44273 is a medium-severity security vulnerability in github.com/consensys/gnark-crypto (go), affecting versions < 0.12.0. It is fixed in 0.12.0.
2. How severe is CVE-2023-44273? CVE-2023-44273 has a CVSS score of 5.1 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/consensys/gnark-crypto are affected by CVE-2023-44273? github.com/consensys/gnark-crypto (go) versions < 0.12.0 is affected.
4. Is there a fix for CVE-2023-44273? Yes. CVE-2023-44273 is fixed in 0.12.0. Upgrade to this version or later.
5. Is CVE-2023-44273 exploitable, and should I be worried? Whether CVE-2023-44273 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
6. What actually determines whether CVE-2023-44273 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.
7. How do I fix CVE-2023-44273? Upgrade github.com/consensys/gnark-crypto to 0.12.0 or later.