QA Report

[code423n4]

1. Use a buggy solidity version with immutables. The contract use immutable, and this solidity version defined in the pragma has some issues with them, as you can see here.

Affected source:

• UUPSUpgradeable.sol#L4-L23

2. Unsecure Ownership Transfer The modification process of an owner is a delicate process, since the governance of our contract and therefore of the project may be at risk, for this reason it is recommended to adjust the owner’s modification logic, to a logic that allows to verify that the new owner is in fact valid and does exist. It's mandatory to create a logic of the owner’s modification where a new owner is proposed first, the owner accepts the proposal and, in this way, we make sure that there are no errors when writing the address of the new owner.

Affected source:

• Ownable.sol#L60

3. Avoid double events and calls. If the caller call twice to the method with the same values, the state wont change but an event will be emitted.

   • Pausable.sol#L70
   • Pausable.sol#L78
   • Pausable.sol#L86
   • Blocklistable.sol#L76
   • Blocklistable.sol#L85
   • Blocklistable.sol#L90
   • FiatTokenV1.sol#L344
   • FiatTokenV1.sol#L377
   • FiatTokenV2.sol#L354)
   • FiatTokenV2.sol#L387
   • FiatTokenV2.sol#L645
   • FiatTokenV2.sol#L654
   • FiatTokenV2.sol#L659

4. There are test code outside test folder:

   • FiatTokenV2test.sol#L8