Can a Decentralized Exchange Be Vulnerable to a 51% Attack?

Yes, a decentralized exchange (DEX) can be vulnerable to a 51% attack, although the attack would target the underlying blockchain rather than the DEX itself. If the blockchain on which the DEX is built is successfully attacked, the attacker could reverse transactions that were made on the DEX.

This could lead to a loss of funds for users of the DEX. To mitigate this risk, DEXs should be built on blockchains with a high hash rate and a strong security model.