Vameon - Audit 1

In the contract `Vameon` the role `_owner` has authority over the functions shown in the diagram below. Any compromise to the `_owner` account may allow the hacker to take advantage of this authority and change fee receive address or trust forwarder address. 

`transferWithFee` requires `_msgSender` to pay a fee to fee collector to perform a transaction. From a user's perspective, they can use `transfer` function instead of `transferWithFee` to avoid fees.

The variable `_trustedForwarder` serves as a 3rd party forwarder to help the `ERC2771Recipient` identify the address of the transaction signer. `BaseToken` and `MeldToken` inherit `ERC2771Recipient`, which decodes the `msg.sender` from `msg.data` when called from the forwarder by overriding the `_msgSender()` function. A malicious forwarder may forge the value of _msgSender() and effectively send transactions from any address. The scope of the audit treats these 3rd party forwarders as black boxes and assumes their functional correctness. However, in the real world, 3rd parties can be compromised and this may lead to lost or stolen assets. In addition, upgrades of 3rd parties can possibly create severe impacts. In this project, a compromised trust forwarder can transfer tokens out of any user's address, which imposes a critical risk. The trust forwarder address is set by the owner of the contract. Reference: [EIP-2771](https://eips.ethereum.org/EIPS/eip-2771)