Quantum Secular Labs / Blog / Advisories

CVE-2026-34909: Ubiquiti UniFi OS Path Traversal Vulnerability

CVE-2026-34909 is rated critical with a CVSS v3.1 base score of 10.0 and affects Ubiquiti UniFi OS, along with 31 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-06-23, which means exploitation in the wild has been observed.

Vulnerability description

A malicious actor with access to the network could exploit a Path Traversal vulnerability found in UniFi OS devices to access files on the underlying system that could be manipulated to access an underlying account.

Severity breakdown

CVSS v3.1 10.0: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

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

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Affected products

  • Ui Unifi OS Server: before 5.0.8
  • Ui Unifi Cloud Gateway Industrial Firmware: before 5.1.12
  • Ui Unifi Dream Machine Firmware: before 5.1.12
  • Ui Unifi Dream Machine Pro Firmware: before 5.1.12
  • Ui Unifi Dream Machine Special Edition Firmware: before 5.1.12
  • Ui Unifi Dream Machine Pro Max Firmware: before 5.1.12
  • Ui Enterprise Fortress Gateway Firmware: before 5.1.12
  • Ui Unifi Dream Wall Firmware: before 5.1.12
  • Ui Unifi Dream Router Firmware: before 5.1.12
  • Ui Unifi Dream Router 7 Firmware: before 5.1.12
  • Ui Unifi Express 7 Firmware: before 5.1.12
  • Ui Unifi Network Video Recorder Firmware: before 5.1.12
  • Ui Unifi Network Video Recorder Pro Firmware: before 5.1.12
  • Ui Unifi Network Video Recorder Instant Firmware: before 5.1.12
  • Ui Enterprise Network Video Recorder Firmware: before 5.1.12

References