A chargeback is a payment reversal initiated by the card issuer after a cardholder disputes a transaction. It can happen when a purchase is unauthorized, the product was not received, or the customer claims the charge was incorrect. In practice, the reversal pulls money back from the merchant and often adds fees and operational overhead.
In cyber security, chargebacks matter because they are a visible sign of fraud loss, especially in card-not-present commerce. They may point to stolen card data, account takeover, or abuse of a checkout flow. Defenders track chargeback rates to spot patterns, tune fraud controls, and measure whether prevention systems are blocking bad activity without rejecting too many legitimate buyers. A low chargeback count is useful, but it does not capture every risk, so teams usually combine it with signals from authentication, transaction monitoring, and account security.