Capcom has acknowledged in a press release that some of its internal systems were hacked earlier this week, however, it does not believe any user data has been leaked.
According to the statement, the hack took place early on Monday morning, and that some of Capcom's networks experienced issues, including email and file servers. Capcom confirmed this was due to "unauthorized access" by a third party, and has halted some operations on its internal networks.
Capcom does not believe that any customer information was breached "at present," although that term does suggest the possibility evidence may yet be found. In any case, it's better to be safe than sorry and assume any details associated with a Capcom account have been leaked.
Capcom is working with the authorities and is conducting an investigation into the incident.