CVE-2026-34909

An attacker with access to the network where the UniFi OS device is operating can send a specially crafted request containing path traversal sequences (e.g., '../'). This allows escaping the allowed directory and reading arbitrary files at the operating system level. The read files may contain authentication or configuration data, whose manipulation enables system account takeover.

An attacker can gain unauthorized access to sensitive system files and take control of an account in the device's operating system, potentially leading to complete device takeover.

Security patches available from the manufacturer should be applied according to the references: https://community.ui.com/releases/Security-Advisory-Bulletin-064-064/84811c09-4cf4-42ab-bd61-cc994445963b

Devices running UniFi OS — specific versions indicated in the manufacturer's references (Security Advisory Bulletin 064).

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Ubiquiti UniFi OS contains a path traversal vulnerability which could allow a malicious actor with access to the network to access files on the underlying system that could be manipulated to access an underlying account.