How Does a Double-Spend Attack Impact the Finality of Transactions in a Blockchain?

A double-spend attack completely destroys the finality of the targeted transactions. Finality means a transaction, once confirmed, cannot be reversed.

By executing a double-spend, the attacker reverses a transaction that was previously confirmed, making the recipient's acceptance of the payment invalid. This loss of finality severely erodes trust in the cryptocurrency as a medium of exchange.