About half of Americans in 2016 didn't trust social media sites to keep safe tabs on their data. The Pew Research Center reposted that fact Friday with the latest Facebook news: The site has discovered a breach that affected about 50 million users, reports the New York Times. The company says the problem has been fixed and it was still assessing just how serious it was, but the personal information of those users was exposed. In a blog post, the company said "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." That, in turn, let the hackers get their hands on what are called "access tokens"—basically, digital "keys"—to hijack people's accounts.
The company says it has temporarily turned off the "View As" feature while it looks into things. It has also reset the access tokens, which meant about 90 million people had to log back onto Facebook or its other apps that use the Facebook login. Facebook says it's not yet sure who the hackers are, where they attacked from, or how big the attack really was. The company says no one has to change their passwords as a result of this attack. "We're taking it very seriously," CEO Mark Zuckerberg said in a conference call to reporters. (More Facebook stories.)