CNN:

A data breach at a payments processing firm has potentially compromised credit and debit card information from all of the major card brands, representatives from MasterCard and Visa said on Friday.
News of the breach was first reported by the respected security blog Krebs on Security. That article said the breach was "massive," and could involve more than 10 million card numbers.
The Wall Street Journal followed up with an article saying that processor Global Payments is the vendor that was breached. Global Payments (GPN) shares fell 9% before trade was halted in the morning. As of 3 p.m. ET, the stock had not resumed trading.
A representative of Global Payments did not respond to a request for comment. The extent of the breach, and what kind of information was compromised, has not been confirmed.