CVE-2026-75520
Domoticz: Missing authorization and path traversal in the udevices Lua parser handler
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
5.4
Domoticz: Missing authorization and path traversal in the udevices Lua parser handler
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.
- Record
CVE-2026-75520- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-22, CWE-862
- Updated
- 2026-11-03
EUVDEUVD-2026-112548
5.4
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.
- Record
EUVD-2026-112548- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Updated
- 2026-11-03
NVD
5.4
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.
- Record
CVE-2026-75520- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-22, CWE-862
- Updated
- 2026-11-03
OSV
5.4
Domoticz: Missing authorization and path traversal in the udevices Lua parser handler
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.
- Record
CVE-2026-75520- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-22, CWE-862
- Updated
- 2026-11-05
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | CVE List, EUVD, NVD | |
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-75520 is a medium vulnerability (CVSS 5.4) in Domoticz, published October 28, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.28%, the 20th percentile. No source names a fixed version.
References
github.com/domoticz/domoticz/security/advisories/GHSA-8rv5-x8wv-c5c4
github.com/domoticz/domoticz/commit/73ed0495af6de3309f27cfc0091e803300ab5ccd
github.com/domoticz/domoticz/blob/2026.3/main/WebServerCmds.cpp
github.com/domoticz/domoticz/releases/tag/2026.3
github.com/domoticz/libwebem/blob/dfe946fa32f4c211662e47ef55b8cedfc50a6a76/include/libwebem/session.h
github.com/CVEProject/cvelistV5/tree/main/cves/2026/75xxx/CVE-2026-75520.json
nvd.nist.gov/vuln/detail/CVE-2026-75520