Facebook has said “almost 50 million” of its users were left exposed by a security flaw.
The company said attackers were able to exploit a vulnerability in a feature known as “View As” to gain control of people's accounts.
According to a report sighted by YEN.com.gh on BBC.com, the breach was discovered on Tuesday, Facebook said, and it has informed police.
Users that had potentially been affected were prompted to re-log-in on Friday, September 28.
Facebook CEO, Mark Zuckerberg took to his wall to address the issues and update users on the security issue.
Excerpts of his post read, "On Tuesday, we discovered that an attacker exploited a technical vulnerability to steal access tokens that would allow them to log into about 50 million people's accounts on Facebook.
We do not yet know whether these accounts were misused but we are continuing to look into this and will update when we learn more."
He went on to elaborate a number of steps the social media company had taken to address the issue.
The flaw has been fixed, wrote the firm’s head of security, Guy Rosen.
"Since we’ve only just started our investigation, we have yet to determine whether these accounts were misused or any information accessed. We also don’t know who’s behind these attacks or where they’re based.“
He added: "People’s privacy and security is incredibly important, and we’re sorry this happened."
Facebook is one of the world's largest social media platform which has connected many people across the world.