Customers and employees of several Carnival Corp. cruise lines might have had personal information stolen. The Miami-based company said Thursday that a data breach in March might have exposed things like Social Security numbers and dates of birth for some customers, employees and ship crew members on Carnival Cruise Line, Holland America Line and Princess Cruises. The company isn’t saying how many people could have had their information exposed. Carnival spokesman Roger Frizzell says the company detected the intrusion to its information-technology systems on March 19 and shut it down, then hired a cybersecurity company to investigate.