said a security breach may have exposed some 40 million cards of all brands to fraud.
MasterCard, a group of banks that issues credit and debit cards, said it is notifying its member financial institutions of the breach. The company said that about a third of the cards potentially exposed are MasterCards.
MasterCard said the breach occurred at Tucson, Ariz.-based CardSystems Solutions, a third-party processor of payment card data. A message seeking comment from CardSystems' Atlanta office wasn't immediately returned.
MasterCard said it found vulnerabilities that allowed an unauthorized individual to infiltrate the CardSystems' network and access the cardholder data.
CardSystems has already taken steps to improve the security of its system, but MasterCard said it "is giving it a limited amount of time to demonstrate compliance with MasterCard security requirements."
The news comes as worries grow over the integrity of personal data in big companies' hands. Earlier this month
indicated about 3.9 million of its mortgage customers may have had their data compromised when
lost a box full of credit data tapes.