Domoticz: Missing authorization and path traversal in the udevices Lua parser handler

{
  "id": "2a5cb4cdb92c7e90edaa076936ae04fcd2676ad95a99d3e462be8463343bd5a1",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-75520",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Domoticz: Missing authorization and path traversal in the udevices Lua parser handler",
    "summary": "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.",
    "evidence": "cve:CVE-2026-75520",
    "products": [
      {
        "name": {
          "value": "domoticz",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-75520",
      "aliases": [
        "CVE-2026-75520"
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "scope": "UNCHANGED",
            "version": "3.1",
            "baseScore": 5.4,
            "attackVector": "NETWORK",
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
            "integrityImpact": "LOW",
            "userInteraction": "NONE",
            "attackComplexity": "LOW",
            "availabilityImpact": "NONE",
            "privilegesRequired": "LOW",
            "confidentialityImpact": "LOW"
          }
        }
      ],
      "affected": [
        {
          "vendor": "domoticz",
          "product": "domoticz",
          "versions": [
            {
              "status": "affected",
              "version": "<= 2026.2"
            }
          ]
        }
      ],
      "modified": "2026-10-28T22:30:59.693Z",
      "provider": "cve",
      "references": [
        "https://github.com/domoticz/domoticz/security/advisories/GHSA-8rv5-x8wv-c5c4",
        "https://github.com/domoticz/domoticz/commit/73ed0495af6de3309f27cfc0091e803300ab5ccd",
        "https://github.com/domoticz/domoticz/blob/2026.3/main/WebServerCmds.cpp#L3445-L3451",
        "https://github.com/domoticz/domoticz/releases/tag/2026.3",
        "https://github.com/domoticz/libwebem/blob/dfe946fa32f4c211662e47ef55b8cedfc50a6a76/include/libwebem/session.h#L10-L17"
      ],
      "provider_metadata": {
        "cna": {
          "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
          "shortName": "GitHub_M",
          "dateUpdated": "2026-10-28T22:30:59.693Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-75520",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 501195,
  "published_at": "2026-10-28T22:30:59.693+00:00"
}