What Are the Differences between Front-Running in Traditional Finance and on DEXs?

In traditional finance (TradFi), front-running is illegal and typically involves a broker using privileged information about a client's pending order to trade for their own benefit. On Decentralized Exchanges (DEXs), front-running is often permissible and is based on public information from the mempool, not private client data.

The TradFi version relies on a breach of fiduciary duty, while the DEX version is a technological race based on transaction fees and speed, viewable by anyone.