Tor browser has been updated to version 10.0.18 with fixes for multiple issues, including a privacy-defeating bug that could be used to uniquely fingerprint users across different browsers based on the apps installed on a computer. The issue has serious implications for privacy as it could be exploited by adversaries to unmask Tor users by correlating their browsing activities as they switch to a non-anonymizing browser such as Google Chrome. Tor users are recommended to move quickly to apply the update to ensure they are protected.
Source: https://thehackernews.com/2021/06/patch-tor-browser-bug-to-prevent.html