The Official Facebook Chat Plugin, a WordPress plugin installed on over 80,000 sites, is a simple plugin that adds a “Facebook Messenger” chat pop-up to a WordPress site and connects a chosen Facebook page to receive messages and interact with site visitors.
A flaw was discovered taking advantage of this, which made it possible for low-level authenticated attackers to connect their own Facebook Messenger account to any site and engage in chats themselves.
We highly recommend updating to version 1.6 immediately to keep your site protected against any attacks attempting to exploit this vulnerability.
For more information please check the official public release.
If you have questions, don’t hesitate to contact our support team.