It is being reported that 50 million users of the social networking site Facebook have been compromised. An additional 40 million accounts have been forcibly 'signed out' requiring users to sign back in to view their profile. The hack has occurred using the 'View As' function which is a privacy function that allows people to see what their profile looks like to other users. Hackers have been able to use this feature to steel Facebook access tokens - digital keys that allow people to stay logged in to Facebook so they don't need to re enter their log in information each time hey access the site.
What to do now
Whenever a hack has been discovered it is always wise to reset your login password. Make sure you log out of Facebook on all your devices you use and reset your password.
Further information can be found by checking out the BBC story: