Front-Running

An attack where an adversary observes a pending or not-yet-finalized transaction (e.g., a large swap or NFT mint) and submits a competing transaction with higher priority fees or via validator relationships to execute before the victim's transaction, profiting from predictable price impact. On Solana, transactions are not held in a public mempool the same way as in Ethereum — leaders receive transactions privately — but front-running is still possible through Jito's block engine bundle mechanism, validator collusion, or by monitoring gossip. Slippage tolerance parameters and commit-reveal schemes are the primary application-level defenses.