If you're on Facebook, you could be at risk. Facebook just discovered a security issue that allowed hackers to access information that could have let them take over around 50 million accounts.

CNBC reports that the Facebook engineering team found that attackers identified a weakness in Facebook's code regarding its "View As" feature. Facebook became aware of a potential attack after it noticed a spike in user activity on September 16th.

"This is a very serious security issue, and we're taking it very seriously," said CEO Mark Zuckerberg on a call with reporters."

"View As" lets users see what their profile looks like to other users on the platform. Almost 50 million accounts had their access tokens taken