https://techcrunch.com/2018/09/28/facebook-says-50-million-accounts-affected-by-account-takeover-bug/

Facebook has said 50 million user accounts may be at risk after hackers exploited a security vulnerability on the site.

The company said in a blog post Friday that it discovered the bug earlier in the week. The bug is part of the site’s “View As” feature that lets a user see their profile as someone else. Facebook has switched off the “View As” feature in the meantime while it investigates the bug further.