OpenZeppelin Contracts's SignatureChecker may revert on invalid EIP-1271 signers

Impact

SignatureChecker.isValidSignatureNow is not expected to revert. However, an incorrect assumption about Solidity 0.8’s abi.decode allows some cases to revert, given a target contract that doesn’t implement EIP-1271 as expected.

The contracts that may be affected are those that use SignatureChecker to check the validity of a signature and handle invalid signatures in a way other than reverting. We believe this to be unlikely.

Patches

The issue was patched in 4.7.1.

References

https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3552

For more information

If you have any questions or comments about this advisory, or need assistance deploying the fix, email us at [email protected].