Summary

Re Entrancy attack

Vulnerability Details

In the context of this contract, the line msg.sender.call{value: msg.value - fees}("") is used to refund the excess payment to the sender after deducting the fees. The call function is used to send an arbitrary message to msg.sender (the address of the sender) and execute the fallback function of the contract. The {value: msg.value - fees} part specifies the amount of Ether to be sent along with the call.

Impact

It is important to note that using call can be dangerous if not used correctly, as it allows arbitrary calls to any contract and can result in reentrancy attacks or other security vulnerabilities.

Tools Used

VIsual inspection

Recommendations

Use re-entrancy guards