Submission Details
Severity:
Lack of slippage protection in TSwapPool::swapExactOutput causes users to potentially receive way fewer tokens
Summary
The swapExactOutput function does not include any sort of slippage protection. This function is similar to what is done in TSwapPool::swapExactInput, where the function specifies a minOutputAmount, the swapExactOutput function should specify a maxInputAmount.
Impact
If market conditions change before the transaciton processes, the user could get a much worse swap.
Recommendations
We should include a maxInputAmount so the user only has to spend up to a specific amount, and can predict how much they will spend on the protocol.
function swapExactOutput(
IERC20 inputToken,
+ uint256 maxInputAmount,
.
.
.
inputAmount = getInputAmountBasedOnOutput(outputAmount, inputReserves, outputReserves);
+ if(inputAmount > maxInputAmount){
+ revert();
+ }
_swap(inputToken, inputAmount, outputToken, outputAmount);
Updates
Appeal created
inallhonesty about 1 year ago
Submission Judgement Published Assigned finding tags:
Lack of slippage protection in `TSwapPool::swapExactOutput` causes users to potentially receive way fewer tokens
Rewards breakdown
nSLOC
276This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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