CVE-2026-71279
HIGHCVE-2026-71279 is a high-severity (CVSS 8) Path Traversal vulnerability. O3 Security confirms whether CVE-2026-71279 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Zigbee2MQTT's ExternalJSExtension.getFilePath() (lib/extension/externalJS.ts) joins a `name` parameter received via an MQTT message (topic zigbee2mqtt/bridge/request/extension/save)…
Description
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.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-71279 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-71279 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-71279. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-71279 in your dependencies?
O3 detects CVE-2026-71279 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.