Security researcher: Anyone can see links you share using Facebook Messenger
When you use a messaging service like Facebook Messenger, you have a reasonable expectation that what you say is private and secure. But due to a quirk in how Facebook handles certain pieces of information, just about anyone who knows how to use Facebook’s developer API can view links that others have sent over Facebook Messenger.
In a post published to Medium, security researcher Inti De Ceukelaire explains how this works. Without getting too technical, every link you share—as well as just about anything else that’s ever been shared to Facebook—has an identification number of sorts assigned to it. As De Ceukelaire notes, “there’s absolutely nothing wrong with this. At least when this data is kept secret.”