On June 26, 2020, Wordfence’s threat intelligence team discovered a vulnerability in The Official Facebook Chat Plugin, a WordPress plugin installed on over 80,000 sites. This flaw made it possible for low-level authenticated attackers to connect their own Facebook Messenger account to any site running the vulnerable plugin and engage in chats with site visitors on affected sites.
Researchers initially reached out to Facebook on June 26, 2020 and included the full disclosure details at the time of reaching out. They initially responded on June 30, 2020, and after much back and forth, Facebook released a patch on July 28, 2020.
In their blog highlighting their findings, Wordfence’s researchers highly recommend updating to version 1.6 immediately to keep your site protected against any attacks attempting to exploit this vulnerability.