Facebook's privacy bug has unlocked blocked people

Matt McClain | The Washington Post | Getty Images

Facebook CEO Mark Zuckerberg

A Facebook bug briefly unlocked people on Messenger who had previously been blocked, opening the door to unwanted messages and exposing otherwise hidden messages, announced Monday the company. .group> p: first-child "/>

The bug has affected up to 800,000 users and has since been corrected, the company said. But that's yet another privacy breach for the social media company, which has been experiencing its mistakes more and more frequently in recent months.

"We know that the ability to block someone is important – and we would like to apologize and explain what happened," said Erin Egan, chief privacy officer, in a blog post

block someone on Facebook means the person can not see any of the user's posts or start conversations on messenger. But the bug, which was active between May 29th and June 5th, allowed previously blocked users to see shared posts with a wider audience (such as friends) and to make a message to them. user who blocked them.

only unlocked a person on the blocked list of a user, Facebook said. Affected users will see a Facebook notification encouraging them to check their blocked lists.