Facebook looks bad luck this year. It is better to invite Chinese Feng Shui master provides suggestion. Yes, it is kidding.

Perhaps Facebook intend to improve their image. It immediately let’s public know what is happening in the moment. It is talking about 6.8 million users’ private photos leakage. But suspected that the loophole was happened in developers environment.
My comment is that may be vulnerability happens in call to action function. A design limitation keep the CTA access token. And therefore it provides unauthorize access.

Headline News: https://www.theverge.com/2018/12/14/18140771/facebook-photo-exposure-leak-bug-millions-users-disclosed