Wizarr: Authenticated Server-Side Template Injection (SSTI) in wizard step rendering leads to Remote Code Execution (RCE)

Wizarr is an advanced user invitation and management system for Jellyfin, Plex, Emby, and other media servers. Prior to 2026.9.1, wizard step Markdown supplied through the editor or imported bundles was evaluated by app/blueprints/wizard/routes.py in the application's non-sandboxed Jinja2 environment with application globals exposed. An authenticated user able to create steps, or an administrator importing an untrusted bundle through POST /settings/wizard/import, could execute arbitrary Python when GET /wizard/{server}/{idx} rendered the stored step; app/jinja_filters.py and app/services/wizard_widgets.py contained additional evaluation sinks. This could execute operating-system commands as the application user, disclose the Flask SECRET_KEY, access connected service credentials and the database, and produce stored cross-site scripting. This issue is fixed in 2026.9.1.