Vulnerability-Lookup

CVE-2026-71279 (GCVE-0-2026-71279)

Vulnerability from cvelistv5 – Published: 2026-08-05 12:26 – Updated: 2026-08-05 15:55

Title

Zigbee2MQTT External JS Extension Path Traversal Leading to Remote Code Execution

Summary

Zigbee2MQTT's ExternalJSExtension.getFilePath() (lib/extension/externalJS.ts) joins a `name` 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. Because path.join() resolves `../` sequences, a name such as `../../tmp/evil.js` escapes the intended extensions directory. 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. Requires the `enable_external_js` config option (off by default, but commonly enabled in legacy installs) and MQTT broker access, which is frequently unauthenticated in real deployments. The identical unsanitized getFilePath() is also used by the extension-removal handler, enabling arbitrary file deletion.

Severity

8.1 (High)


                        
                          CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-22

Assigner

TuranSec

References

2 references

URL	Tags
https://github.com/Koenkk/zigbee2mqtt
https://github.com/Koenkk/zigbee2mqtt/blob/master…

Impacted products

1 product

Vendor	Product	Version
Koenkk	zigbee2mqtt	Affected: 0 , ≤ 2.12.0 (semver)

Credits

Alibek Baxtiyorov

Show details on NVD website

JSON

To clipboard

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GHSA-77VH-G47P-VH46

Vulnerability from github – Published: 2026-08-05 15:32 – Updated: 2026-08-05 15:32

Details

Zigbee2MQTT's ExternalJSExtension.getFilePath() (lib/extension/externalJS.ts) joins a name 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. Because path.join() resolves ../ sequences, a name such as ../../tmp/evil.js escapes the intended extensions directory. 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. Requires the enable_external_js config option (off by default, but commonly enabled in legacy installs) and MQTT broker access, which is frequently unauthenticated in real deployments. The identical unsanitized getFilePath() is also used by the extension-removal handler, enabling arbitrary file deletion.

Severity

8.0 (High)


                  
                    CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-71279"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-05T13:24:52Z",
    "severity": "HIGH"
  },
  "details": "Zigbee2MQTT\u0027s ExternalJSExtension.getFilePath() (lib/extension/externalJS.ts) joins a `name` 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. Because path.join() resolves `../` sequences, a name such as `../../tmp/evil.js` escapes the intended extensions directory. 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. Requires the `enable_external_js` config option (off by default, but commonly enabled in legacy installs) and MQTT broker access, which is frequently unauthenticated in real deployments. The identical unsanitized getFilePath() is also used by the extension-removal handler, enabling arbitrary file deletion.",
  "id": "GHSA-77vh-g47p-vh46",
  "modified": "2026-08-05T15:32:20Z",
  "published": "2026-08-05T15:32:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-71279"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Koenkk/zigbee2mqtt"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Koenkk/zigbee2mqtt/blob/master/lib/extension/externalJS.ts"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-71279 (GCVE-0-2026-71279)

GHSA-77VH-G47P-VH46

Tags

Sightings

Nomenclature