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, CmdUpdateDevices 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 luaLloadfile. 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.

Domoticz versions prior to 2026.1 contain a stored cross-site scripting vulnerability in the Add Hardware and rename device functionality of the web interface that allows authenticated administrators to execute arbitrary scripts by supplying crafted names containing script or HTML markup. Attackers can inject malicious code that is stored and rendered without proper output encoding, causing script execution in the browsers of users viewing the affected page and enabling unauthorized actions within their session context.