Talk about a cache flow problem: This JavaScript can snoop on other browser tabs to work out what you're visiting

Yes, even the Tor browser can be spied on by this nasty code

Special report Computer science boffins have demonstrated a side-channel attack technique that bypasses recently-introduced privacy defenses, and makes even the Tor browser subject to tracking. The result: it is possible for malicious JavaScript in one web browser tab to spy on other open tabs, and work out which websites you're visiting."