Domoticz up to 2026.2 Lua Script main/LuaHandler.cpp executeLuaScript script privileges management

Summaryinfo

A vulnerability labeled as critical has been found in Domoticz up to 2026.2. This issue affects the function CLuaHandler::executeLuaScript of the file main/LuaHandler.cpp of the component Lua Script Handler. The manipulation of the argument script results in privileges management. This vulnerability is identified as CVE-2026-75520. The attack can be executed remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in Domoticz up to 2026.2. Affected is the function CLuaHandler::executeLuaScript of the file main/LuaHandler.cpp of the component Lua Script Handler. The manipulation of the argument script with an unknown input leads to a privileges management vulnerability. CWE is classifying the issue as CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-75520 since 08/17/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1068.

Upgrading to version 2026.3 eliminates this vulnerability.

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Productinfo

Name

• Domoticz

Version

• 2026.0
• 2026.1
• 2026.2

Website

• Product: https://github.com/domoticz/domoticz/

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