OpenZeppelin Contracts is a library for smart contract development. Versions 4.1.0 until 4.7.1 are vulnerable to the SignatureChecker reverting. 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. The issue was patched in version 4.7.1.

OpenZeppelin Contracts is a library for smart contract development. In affected versions upgradeable contracts using UUPSUpgradeable may be vulnerable to an attack affecting uninitialized implementation contracts. A fix is included in version 4.3.2 of @openzeppelin/contracts and @openzeppelin/contracts-upgradeable. For users unable to upgrade; initialize implementation contracts using UUPSUpgradeable by invoking the initializer function (usually called initialize). An example is provided in the forum.