The Facebook Sync feature for the iPhone has published the contact details of a number of users.
Facebook’s ‘Contact Sync’ app for Apple’s iPhone may have lead users to leak their personal contact details and that of their friends and relatives on the website unknowingly, tech news site Tech Eye reports.
"The implications are huge, and extremely worrying. All it takes is for someone's Facebook account to be hacked (perhaps via their phone being stolen) and lots of personal details are revealed," English daily the Guardian read.
The report states that the website regulators do not warn app users before uploading their personal information on its server.
However, in an update Facebook, has denied allegations of storing and publicly displaying the phone details of any of its iPhone app users.
The web page now tells users to disable the sync feature completely if they want to remove their personal details.
Neither Facebook nor Apple have commented on the issue.