Major Credit Card Security Breach May Affect Up To 10 Million MasterCard, Visa Customers

NEW YORK (CBSNewYork) -- Some major credit card companies are warning their customers that their account information may have fallen into the wrong hands.

As many as 10 million MasterCard and Visa customers may be victims of the latest big credit card security breach, according to cyber crime blogger Brian Krebs of krebsonsecurity.com.

WCBS 880's Monica Miller On The Story

"It looks like a credit/debit card processor had a security breach of some kind that seems to have jeopardized a whole bunch of cards," Krebs told WCBS 880's Monica Miller.

Both MasterCard and Visa said that their own systems have not been compromised, but the security of the outside payment-processor they use may have been breached.

The breach was at a company that acts as a middleman between banks and merchants, handling payments for both credit and debit cards. The Wall Street Journal identified the company as Global Payments, based in Atlanta.

Mastercard released the following statement on Friday:

"MasterCard is currently investigating a potential account data compromise event of a U.S.-based entity and, as a result, we have alerted payment card issuers regarding certain MasterCard accounts that are potentially at risk.

"MasterCard is concerned whenever there is any possibility that cardholders could be inconvenienced and we continue to both monitor this event and take steps to safeguard account information. If cardholders have any concerns about their individual accounts, they should contact their issuing financial institution.

"Law enforcement has been notified of this matter and the incident is currently the subject of an ongoing forensic review by an independent data security organization. It is important to note that MasterCard's own systems have not been compromised in any manner."

Authorities may have pinpointed where the stolen credit cards were spent, according to Krebs.

"The few folks I've talked to within the financial services industry tell me it's pretty big," Krebs added.

The authorities have been put on alert, as well as the banks that issue the credit cards.

Both Visa and MasterCard rushed to reassure customers that they won't be held responsible for fraudulent charges.

How concerned does this make you as a credit card holder, even if you weren't affected this time? Sound off with your comments below...