Over 800,000 people were impacted by a bug in Facebook and Messenger that unblocked people they had previously blocked. This meant that, between May 29 and June 5, those people could be contacted by those they actively took measures to prevent contacting them.

Facebook’s privacy boss Erin Egan explained the bug:

“When you block someone on Facebook they cannot see things you post on your profile, start conversations with you on Messenger or add you as a friend. Blocking also automatically unfriends them if you were previously friends. In the case of this bug:

• It did not reinstate any friend connections that had been severed;


• 83% of people affected by the bug had only one person they had blocked temporarily unblocked; and


• Someone who was unblocked might have been able to contact people on Messenger who had blocked them.”

Those affected will get a notification from Facebook explaining the error, and “encouraging them to check their blocked list.”

In this era of increased security fear, a screw-up like this is a major blow to Facebook’s already-damaged perception.

The article was originally published on Brag Magazine