Vulnerability Details

In https://github.com/Cyfrin/2023-12-the-standard/blob/main/contracts/LiquidationPool.sol#L207 and https://github.com/Cyfrin/2023-12-the-standard/blob/main/contracts/LiquidationPool.sol#L218, the protocol uses Chainlink latestRoundData() but it does not check for stale prices, on top of that it doesn't check whether the Arbitrum sequencer is down too which can also result in stale price.

Impact

If there is a large fluctuation in price while reported prices are stale then it could lead to wrong price being used in calculation of the amount of EUROs to burn resulting in wrong amount of EUROs burnt.

Tools Used

Manual Review.

Recommendations

Check for stale prices in Chainlink aggregator function and that the Arbitrum sequencer is up.