Summary

Ownable implements a simplified process for transferring ownership in a single step.

Vulnerability Details

Single-step ownership transfer means that if a wrong address was passed when transferring ownership or admin rights it can mean that role is lost forever. If the admin permissions are given to the wrong address within this function, it will cause irreparable damage to the contract.
Below is the official documentation explanation from OpenZeppelin：
https://docs.openzeppelin.com/contracts/4.x/api/access

Ownable is a simpler mechanism with a single owner "role" that can be assigned to a single account. This simpler mechanism can be useful for quick tests but projects with production concerns are likely to outgrow it.
The Messaging contract inherits from the Ownable contract, where the ownership transfer is a single-step process, posing the aforementioned risk.

The collection_transfer_ownership() function in the bridge.cairo contract also has the same issue.

Impact

Ownership (administrative privilege) can be lost to an uncontrolled account if the current owner provides an invalid address for the new owner.

Tools Used

Recommendations

It is recommended to use the Ownable2Step contract from OZ (https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/access/Ownable2Step.sol) instead.