MEV Frontrunning

MEV Frontrunning involves malicious actors monitoring the mempool for pending transactions to insert their own trades ahead of others to profit from the price impact. In the context of oracles, frontrunners observe a pending oracle update transaction that will significantly change the asset price.

They then execute a transaction to trade against the current stale price before the update is confirmed. By paying a higher gas fee to miners or validators, they ensure their trade is processed first, capturing the spread created by the latency.

This practice extracts value from liquidity providers and protocol users, effectively acting as a hidden tax on decentralized trading. It is a classic example of adversarial behavior in a transparent, permissionless system.

Sophisticated protocols now use private mempools or batch auctions to combat this predatory behavior.