Facebook bug affects 800,000 users in randomly unblocking people

Facebook said Monday that more than 800,000 users may have been affected by a bug which would randomly unblock some people whom users have blocked on the site.

Erin Egan, chief privacy officer at Facebook, said the bug was active in both Facebook and Messenger between May 29 and June 5, which prevented someone who was unblocked from seeing content shared with friends.

With the bug, "83 percent of people affected by the bug had only one person they had blocked temporarily unblocked," Egan wrote in an official post.

However, he said the bug has been fixed and everyone has been blocked again.

Egan did not disclose how the bug occurred and why it existed for a week, and she said people created block lists for several reasons, including a changed relationship, a break from "annoying" contents, or other serious cases like harassment or bullying.

This is the second software bug in less than a month that the company has notified users about.

In June, Facebook reported a software bug that enabled some users to post publicly by default no matter how their previous settings were.

Up to 14 million users were affected by the bug for several days in May.