# CVE-2026-71279: Zigbee2MQTT External JS Extension Path Traversal Leading to Remote Code Execution

> Attackers can achieve remote code execution in Zigbee2MQTT by exploiting a path traversal vulnerability in the external JS extension handler.

- **Severity:** High 8.1 (`CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 5 Aug 2026
- **Updated:** 10 Aug 2026
- **Also known as:** GHSA-77vh-g47p-vh46

## What is CVE-2026-71279?

CVE-2026-71279 is a high-severity path traversal vulnerability in Koenkk zigbee2mqtt, published on 5 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-71279?


## How do I fix CVE-2026-71279?

No fix has been published for CVE-2026-71279 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-71279 being exploited?

There is no known exploitation of CVE-2026-71279 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-71279 and fix it if it is affected.

What it is: CVE-2026-71279 is a high-severity path traversal vulnerability in Koenkk zigbee2mqtt, published on 5 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-71279 in the wild and no public exploit code.

Affected product: Koenkk zigbee2mqtt. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-71279/ (Markdown: https://insights.sbomify.com/CVE-2026-71279/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-71279
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-71279
- OSV: https://osv.dev/vulnerability/CVE-2026-71279

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-71279/
Summaries are generated and may contain mistakes; the official description above is the record.