The bug was noticed late Wednesday by Tom Krieglstein, founder of Chicago-based technology training company Swift Kick, who found he had been granted administrative access to Pages belonging to Microsoft, Southwest Airlines and American Airlines. "I was just looking at my Pages," he said in an interview Thursday. "I noticed that it was showing me other companies' as well."

The largest Page, Star Wars, allowed him to send a message out to more than 825,000 fans.

Facebook users typically set up their own profiles to share information about themselves, but they can also set up Facebook Pages to share information about businesses they own or represent. The popular social network has undergone a major redesign in recent weeks, including a revamped version of Facebook Pages

Krieglstein believes a glitch in the redesign allowed him to get control of the Pages. To test that he really did have administrative control, he sent out a link to the Star Wars group of a child playing the movie's theme song on a harp. Within a few hours, about 450 people had clicked on the link.

Krieglstein said he could have kicked other administrators off the Pages, added content, or even deleted the Pages altogether.