Sablier

Summary

approve() function is called without setting the allowance to zero.

Vulnerability Details

function _approve(address sablierContract, IERC20 asset, uint256 amount) internal {
uint256 allowance = asset.allowance({ owner: address(this), spender: sablierContract });
if (allowance < amount) {
@>> asset.forceApprove({ spender: sablierContract, value: amount });
}
}

Impact

approve() function is called without setting the allowance to zero. Some tokens, like USDT, require first reducing the address' allowance to zero by calling approve(_spender, 0).

Tools Used

Recommendations

function _approve(address sablierContract, IERC20 asset, uint256 amount) internal {
uint256 allowance = asset.allowance({ owner: address(this), spender: sablierContract });
if (allowance < amount) {
asset.forceApprove({ spender: sablierContract, value: 0 });
asset.forceApprove({ spender: sablierContract, value: amount });
}
}