Tor Browser 8.5.2 has been released to fix a critical vulnerability in Firefox that was fixed by Mozilla this week. It is strongly advised that all Tor users install this update as soon as possible. Unfortunately, the Android version of Tor Browser will not be available until the weekend as part of the Tor team who handles the Android signing token is away at an event. This bug did not affect users running under the Safer or Safest security levels. The bundled NoScript addon has been upgraded to version 10.6.3.
Source: https://www.bleepingcomputer.com/news/software/tor-browser-852-released-to-fix-critical-vulnerability/