Domoticz is a free, open source home automation system for Linux, Windows, macOS, and Raspberry Pi. Prior to 2026.3, the `udevices` JSON com

Domoticz is a free, open source home automation system for Linux, Windows, macOS, and Raspberry Pi. Prior to 2026.3, the udevices JSON command handler, Cmd_UpdateDevices in main/WebServerCmds.cpp, performed no session.rights check before invoking a Lua parser script, while its sibling command handlers gate access by role. A low-privilege authenticated user could trigger execution of an existing operator-installed Lua parser script with attacker-controlled input through the GET /json.htm endpoint with type=command and param=udevices. The script parameter also lacked a .. path-traversal guard: CLuaHandler::executeLuaScript in main/LuaHandler.cpp constructed the filename from the parser directory and the supplied script name before passing it to luaL_loadfile. Execution is limited to already-installed valid Lua files; this is not arbitrary code execution, and the advisory states that file-write and upload paths require administrator privileges. This issue is addressed in version 2026.3.