A spokesman from MasterCard says it is investigating reports of a potential breach at the California Department of Motor Vehicles.
Seth Eisen says the breach is not with MasterCard's systems.
KrebsOnSecurity.com was the first to report the possible breach, which it says involved online payments from Aug. 2, 2013, to Jan. 31, 2014.Eisen says MasterCard has sent out alerts to member banks. He advises consumers to review their accounts and contact their card issuer for assistance.
In a statement, the California Department of Motors Vehicles said that there was no evidence of a direct breach of its computer system.
"However, out of an abundance of caution and in the interest of protecting the sensitive information of California drivers, the DMV has opened an investigation into any potential security breach in conjunction with state and federal law enforcement," it said.
"We will immediately notify any affected DMV customers as quickly as possible if we find any issue," it said.