Facebook has admitted to a bug in its system that has given users of the Download Your Information (DYI) tool "additional email addresses or telephone numbers for their contacts or people with whom they have some connection."
Facebook apologized, stating that it has notified regulators in the US, Canada and Europe, and that it is contacting affected users by email. Security commentators, meanwhile, are trying to work out exactly what happened, and how.
Facebook has admitted that the bug caused the phone numbers and email addresses of six million users to be shared unintentionally. The number of UK users affected by the bug is believed to be around 200,000 according to the Telegraph.