A security vulnerability found on Facebook has been dubbed Originulls a cross-origin bypass-attack which allows the hacker to use an external website to access and read private Facebook messages. The issue was discovered and reported to Facebook by team researcher Ysrael Gurt. Facebook has since fixed the flawed component of the flaw, which also potentially affects millions of websites using origin null restriction checks, threatening user privacy and opening site visitors up to malicious entities. However, Secret Conversations, Facebook Messenger’s end-to-end encrypted chat feature was not affected by this bug.”]
Source: https://gbhackers.com/critical-bug-allows-read-private-chats-facebook-messenger-hackers/