And some of them didn't even realize they were victims of the breach until they went to use their debit cards and realized they didn't work.
The breach apparently left Leslie Page with a $794 negative balance in her account.
Page is the victim of a fraud scam that now stretches across the globe -- from North Carolina to California to Spain to Pakistan.
"I had been out of town over the weekend, but not in Pakistan," Page said.
But someone was using her debit card number in Lahore, Pakistan, to withdraw money. All together, she lost about $900.
Published reports say Visa USA customer account numbers and personal identification numbers were stolen from a major retailer, possibly OfficeMax.
This week, Visa USA notified banks across the nation about the security lapse. The FBI and Secret Service are investigating the case.
Visa said cardholders are not responsible for any fraudulent purchases made with their cards. They are fully protected by the company's zero-liability fraud protection policy.