OpenZeppelin Contracts is a library for smart contract development. Versions 4.0.0 until 4.7.1 are vulnerable to ERC165Checker reverting instead of returning false. ERC165Checker.supportsInterface is designed to always successfully return a boolean, and under no circumstance 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-165 as expected, specifically if it returns a value other than 0 or 1. The contracts that may be affected are those that use ERC165Checker to check for support for an interface and then handle the lack of support in a way other than reverting. The issue was patched in version 4.7.1.

Impact

OpenZeppelin Contracts is a library for secure smart contract development. Starting in version 4.0.0 and prior to version 4.9.3, contracts using ERC2771Context along with a custom trusted forwarder may see msgSender return address(0) in calls that originate from the forwarder with calldata shorter than 20 bytes. This combination of circumstances does not appear to be common, in particular it is not the case for MinimalForwarder from OpenZeppelin Contracts, or any deployed forwarder the team is aware of, given that the signer address is appended to all calls that originate from these forwarders.

Patches

The problem has been patched in v4.9.3.