"How to disable permission to read 'System Fonts' and 'Browser Plugin Details' in Chrome and Firefox"
http://superuser.com/questions/292666/how-to-disable-permiss...
http://superuser.com/questions/292666/how-to-disable-permiss...
You can measure fonts using JS to avoid having to have flash to do font based fingerprinting, eg http://www.lalit.org/lab/javascript-css-font-detect/. There's also the option to attempt to set the font and then get the style of the element and see if it's using the new font (works only on FF and Opera IIRC), eg http://www.quirksmode.org/dom/getstyles.html).
(The third alternative would be to spoof the information on each request, but I don't know how well that would work, and it could cause other problems.)