Submitted by leastwood
purchaseArbitrageTokens enables users to commit collateral tokens and in return receive arbitrage tokens which are redeemable in the future for Malt tokens. Each auction specifies a commitment cap which when reached, prevents users from participating in the auction. However, realCommitment can be ignored by directly sending the LiquidityExtension contract collateral tokens and subsequently calling purchaseArbitrageTokens.
Consider the following scenario:
As a result, a user could effectively influence the average malt price used throughout the Auction contract.
https://github.com/code-423n4/2021-11-malt/blob/main/src/contracts/Auction.sol#L177-L214
https://github.com/code-423n4/2021-11-malt/blob/main/src/contracts/LiquidityExtension.sol#L117-L128
Consider adding a check to ensure that realCommitment != 0 in purchaseArbitrageTokens.
0xScotch (sponsor) confirmed
Alex the Entreprenerd (judge) commented:
