Summary

Use increaseAllowance() instead of approve()/safeApprove()

Vulnerability Details

Changing an allowance with approve() brings the risk that someone may use both the old and the new allowance by unfortunate transaction ordering. Refer to ERC20 API: An Attack Vector on the Approve/TransferFrom Methods. It is recommended to use the increaseAllowance()/decreaseAllowance() to avoid this problem.

Impact

Changing an allowance with approve() brings the risk that someone may use both the old and the new allowance by unfortunate transaction ordering.

Tools Used

Manual Review

Recommendations

Consider using increaseAllowance() instead of approve()/safeApprove()