I'm currently using Tor Browser Bundle version 4.5.1.
In order to pass the verifications set by Cloud Flare so as to gain access to certain websites, I've no choice but to choose the DEFAULT "Privacy Settings" in TBB 4.5.1.
Will the administrators of the websites that I visit know my real IP address through the use of cleverly crafted Javascripts embedded in certain web pages and/or the use of embedded web bugs or persistent cookies?