Facebook Reveals Massive "Security Issue" Affecting 50 Million Users

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As a result of the precautions the company has taken, some 90 million users will be forced to manually log back into their accounts.

On Friday, Facebook, which has been in the public spotlight for concerns about user privacy and data, revealed a massive "security issue" that the company said affects 50 million users.

"Our investigation is still in its early stages," VP of product management Guy Rosen said. "But it’s clear that attackers exploited a vulnerability in Facebook’s code that impacted 'View As,' a feature that lets people see what their own profile looks like to someone else. This allowed them to steal Facebook access tokens which they could then use to take over people’s accounts."

Rosen said in a blog post that Facebook has fixed the vulnerability and informed law enforcement about the issue.

The company is also temporarily suspending the problematic feature as a precaution.

Rosen said that Facebook doesn't know the identity of the cyber attackers. "Since we’ve only just started our investigation, we have yet to determine whether these accounts were misused or any information accessed," he said. "We also don’t know who’s behind these attacks or where they’re based."

As a result of the precautions the company has taken, some 90 million users will be forced to manually log back into their accounts.

"People’s privacy and security is incredibly important, and we’re sorry this happened," Rosen wrote. "It’s why we’ve taken immediate action to secure these accounts and let users know what happened."