Frangiop

**Name of the Vulnerable Software and Affected Versions** OpenZeppelin Contracts versions 4.0.0 through 4.9.3 **Description** OpenZeppelin Contracts is a library for secure smart contract development. 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. **Recommendations** For versions prior to 4.9.3, update to version 4.9.3 to resolve the issue. As a temporary workaround, consider restricting the use of custom trusted forwarders with `ERC2771Context` until the update is applied. Avoid using calldata shorter than 20 bytes in calls that originate from custom trusted forwarders until the issue is resolved.

**Name of the Vulnerable Software and Affected Versions** OpenZeppelin Contracts versions prior to 4.8.3 **Description** A function in the implementation contract may be inaccessible if its selector clashes with one of the proxy's own selectors. Specifically, if the clashing function has a different signature with incompatible ABI encoding, the proxy could revert while attempting to decode the arguments from calldata. The probability of an accidental clash is negligible, but one could be caused deliberately and could cause a reduction in availability. **Recommendations** For versions prior to 4.8.3, update to version 4.8.3 to resolve the issue. As a temporary workaround, if a function appears to be inaccessible for this reason, it may be possible to craft the calldata such that ABI decoding does not fail at the proxy and the function is properly proxied through.