Currency exchange commission is an extra charge added when a payment is made in a currency different from the cardholder’s base currency. Card issuers, payment processors, or merchants may apply it during conversion, so the final cost can be higher than the displayed price. The fee may appear as a percentage of the purchase, a fixed amount, or part of a broader foreign-transaction charge.
This matters in cyber security because online fraud often hides in payment details. A malicious checkout page, a fake travel site, or a compromised merchant flow can steer users into unexpected currency conversion and extra costs. Defenders look for signs such as unusual foreign-currency charges, inconsistent merchant locations, or misleading “no fee” claims. Users reduce risk by checking the billed currency before paying, reviewing card statements, and confirming how cross-border transactions are handled in the card terms.