Zigbee2MQTT External JS Extension Path Traversal Leading to Remote Code Execution

{
  "id": "a3ad2e8965c9faa4a7f9a944869d68fc91d609236c0eba6b91084d3a75009eae",
  "url": "https://osv.dev/vulnerability/CVE-2026-71279",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Zigbee2MQTT External JS Extension Path Traversal Leading to Remote Code Execution",
    "summary": "Zigbee2MQTT's ExternalJSExtension.getFilePath (lib/extension/externalJS.ts) joins a parameter received via an MQTT message (topic zigbee2mqtt/bridge/request/extension/save) into the extensions base path using path.join(basePath, name) with no sanitization. The extension handler only validates that the name ends in .js/.mjs/.cjs, writes the file, and then dynamically imports it via Node.js import, achieving remote code execution.",
    "evidence": "osv:CVE-2026-71279",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-71279",
      "aliases": [
        "CVE-2026-71279"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/koenkk/zigbee2mqtt",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "fd8bafc81d03aa401f41eba5803a3dd1dd8092cd"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "2.12.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.12.0",
            "2.11.0",
            "2.10.1",
            "2.10.0",
            "2.9.2",
            "2.9.1",
            "2.9.0",
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            "2.7.2",
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            "1.13.1",
            "1.13.0",
            "1.12.1",
            "1.12.0",
            "1.11.0",
            "1.10.0",
            "1.9.0",
            "1.8.0",
            "1.7.1",
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            "0.1.2",
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-71279.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:48.334549390Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71279.json",
        "https://github.com/Koenkk/zigbee2mqtt",
        "https://github.com/Koenkk/zigbee2mqtt/blob/master/lib/extension/externalJS.ts",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-71279"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-22"
        ],
        "cna_assigner": "TuranSec",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71279.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-71279",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 516813,
  "published_at": "2026-08-05T12:26:25.594+00:00"
}