The FBI is investigating a security breach in Apple's AT&T network that exposed the personal information of at least 114,000 iPad owners’ accounts. The breached accounts, belonging to an exclusive set of early iPad 3G subscribers, left the personal email addresses and other personal data of thousands of A-listers—including Diane Sawyer, New York Mayor Michael Bloomberg, and White House Chief of Staff Rahm Emanuel—available to anyone with an Internet connection. The FBI said Thursday it is looking into a "potential cyber threat." AT&T closed the security hole that allowed the information to be exposed, but users had been unaware of the situation until now. The snafu is another security embarrassment for Apple, coming just weeks after an early iPhone prototype was picked up at a bar and dissected by the website Gizmodo.