Impact

A bug in Frontier's MODEXP precompile implementation can cause an integer underflow in certain conditions. This will cause a node crash for debug builds. For release builds (and production WebAssembly binaries), the impact is limited as it can only cause a normal EVM out-of-gas. It is recommended that you apply the patch as soon as possible.

If you do not use MODEXP precompile in your runtime, then you are not impacted.

Patches

Patches are applied in PR #549.

Workarounds

None.

References

Patch PR: #549

Credits

Thanks to SR-Labs for discovering the security vulnerability, and thanks to PureStake team for the patches.

For more information

If you have any questions or comments about this advisory:

• Open an issue in the Frontier repo

References

• GHSA-cjg2-2fjg-fph4
• https://nvd.nist.gov/vuln/detail/CVE-2022-21685
• polkadot-evm/frontier#549
• polkadot-evm/frontier@8a93fdc