Phone numbers and email addresses belonging to some 6 million Facebook users have been improperly shared due to a software bug, the social network said on Friday. But no financial or other information was revealed to others, and there was “no evidence that this bug has been exploited maliciously,” Facebook said in a security note, adding it was “upset and embarrassed” by the glitch. Affected users were being notified by email, it said, while stressing that the practical impact was likely to be “minimal,” partly because improper data sharing would only have occurred between users who already had some connection. “We take people’s privacy seriously, and we strive to protect people’s information to the very best of our ability,” it said, but added: “Even with a strong team, no company can ensure 100 percent prevention of bugs.”