Millions of Americans may be at risk of credit card fraud after a recent security breach. More than 2,500 local customers have already been notified they may be on the list.

Cuna Credit Union already sent out notices about the breach to local customers who may have been affected. "There was an information breach with a third party credit card processor out of Atlanta, Georgia. It put 40 million cards at risk for fraud," says Chris Howe from CUNA Credit Union.

Howe says this breach affects both debit and credit card holders for Visa and Mastercard. "A very small percentage of those cards will actually see fraudulent transactions on their cards," Howe adds.

Some of the information leaked included the account number and the customers name. "It's important to know this is not any type of personal information that would put them at risk for anything else other than fraudulent activity on credit card," says Howe.

Howe says if you received a letter this does not mean you are definitely affected. He says CUNA sent out the letters and systematically reissued the cards of those accounts in question just as a precaution.

"In the meantime, they'll want to keep a close eye on their card statements to make sure there aren't any transactions on there that weren't conducted by themselves," says Howe.

To play it safe, experts say never give out any personal information over the phone, or in the form of an unsolicited letter.

They add, if you ever wonder if your financial institution is the one asking for that information, call that your bank, and they'll talk you through what to do.