Medium · published September 22, 2026
Tautulli is a Python based monitoring and tracking tool for Plex Media Server. Prior to 2.17.2, the unauthenticated /auth/redirect endpoint in plexpy/webauth.py removes forward slashes from the user-controlled redirect_uri parameter but leaves tab, line-feed, and carriage-return characters intact. With the default root HTTP_ROOT configuration, CherryPy HTTPRedirect passes the resulting value to urllib.parse.urljoin, which can resolve the whitespace-bearing path to an attacker-controlled external origin. A user who follows a crafted link can therefore be redirected outside Tautulli for phishing or post-login redirect-flow abuse, while custom non-root HTTP_ROOT configurations are not affected by this bypass. This issue is fixed in version 2.17.2.