[Software engineer Robert] Heaton said Stylish has been collecting the browser histories from Chrome users since January, 2017, and from Firefox users since March. Even though the collection was disclosed, it largely escaped the notice of Google, Mozilla, and Opera—not to mention more than two million end users—until Heaton documented it. Officials with Stylish didn’t immediately respond to a request to comment for this post.Once the issue hit the press a couple of days ago, Mozilla, Google and Opera took swift action and banned Stylish. However, this episode is another reminder that the use of browser extensions, even popular ones, isn't without dangers. Besides opening up possible attack routes, they can also secretly be spying on you, as the case of Stylish reveals.
Via: ARS Technica