The problem is that browsers are so complex now and with so many APIs they represent an enormous attack surface. In this case it’s about tracking users without using cookies by exploiting the browser canvas element.
Originally shared by Roberto Bayardo
Ad & cookie blocking is leading to an explosion in browser fingerprinting as an alternate tracking mechanism. Previously limited to the more sketchy corners of the internet, I see it becoming more mainstream. I hope all the major browser developers aggressively try to contain it. I’m not sure it’s possible to eliminate completely without crippling modern browser functionality, but they should at least be able to make it far more difficult. Good move by Firefox here.

