TOR web browser is excellent for hiding your actual IP address but a recent vulnerability exposes your real IP address to certain type of web pages. This vulnerability was discovered by an Italian security researcher, Filippo Cavallarin who said this is already an issue in Firefox which is what is used by TOR browser as well. For some reason, this issue is only faced by Mac and Linux users. Windows users need not worry about anything. Details of this flaw have not been revealed publicly.
This issue happens due to Firefox’s issue in handling file:// URL files. So whenever a user clicks on links that start with file:// address, the actual IP is revealed to the website and they can make out that you are using a proxy web service. This happens because the Mac/Linux directly connects the system to the remote host instead of going through the TOR browser.
Fortunately, this problem has been rectified by the TOR team already and they are pushing the updated versions to the Mac and Linux users already. So before you start browsing the websites again, we request you to update the browser in order to browse anonymously. Another version, v0.3.2.1 alpha is already available that also brings next generation of onion services.