The company says hackers exploited the "View As" feature on the service. Facebook says it has taken steps to fix the security problem and alerted law enforcement.
Facebook data scandal fallout: Cambridge Analytica shuts down all offices
Violence in Azamgarh over Facebook post, 17 held
FB systems do not see the content of messages being transmitted over WhatsApp: Zuckerberg
Congress had a close tie-up with Cambridge Analytica, says Union Min. Ravi Shankar Prasad