Time-of-check Time-of-use (TOCTOU) Race Condition in TeamViewer Windows Installer Rollback Mechanism Leads to Local Privilege Escalation

TeamViewer Full Client and Host prior to version 15.82 on Windows contain a TOCTOU race condition in the installer rollback mechanism. A local low-privileged attacker can replace rollback backup files stored in a user-writable temporary directory before they are restored by an elevated installer, resulting in privilege escalation to NT AUHORITY/SYSTEM. Exploitation requires successful timing of the race condition and a rollback during installation or update.