Exploit vendor drops Tor Browser zero-day on Twitter
It is included with all Tor Browser distributions because it provides an extra layer of security for Tor Browser users. Zerodium’s Tor zero-day basically allows malicious code to run inside the Tor Browser by bypassing NoScript’s script-blocking ability. According to Zerodium, the zero-day affects only the Tor Browser 7.x series.
The Tor Browser 8.x branch, released last week, is not affected. The reason is that the Tor Browser 8.x series switched its underlying codebase from an older Firefox core to the new Firefox Quantum platform, which uses a new add-ons API. The NoScript add-on was rewritten at the end of last year to work on the new Firefox Quantum platform, hence the reason why the zero-day revealed today does not work on the new Tor Browser 8.x series.