CVE-2026-34909: Ubiquiti UniFi OS path traversal in underlying system files

CVE-2026-34909 · Severity: critical · CVSS 10 · Exploited in the wild · Published 2026-05-22

A critical security vulnerability has been identified in Ubiquiti UniFi OS, the software used to manage UniFi networking and security devices. An attacker with network access can bypass security restrictions to read or modify sensitive system files. This could allow them to take full control of the device and its associated accounts, potentially compromising the entire managed network.

Technologies: Ubiquiti EFG, Ubiquiti UDM-Pro, Ubiquiti UDM-Pro-Max, Ubiquiti UDM-SE, Ubiquiti UDR-5G, Ubiquiti UDR7, Ubiquiti UDW, Ubiquiti UniFi OS. Vendors: Ubiquiti.

Quick answers

Is CVE-2026-34909 exploited in the wild?
Yes. CVE-2026-34909 is known to be exploited in the wild, first recorded on 23 June 2026. Treat it as urgent.
How severe is CVE-2026-34909?
Critical severity, with a CVSS score of 10, published 22 May 2026.
Which products and versions are affected?
Ubiquiti EFG < 5.1.12; Ubiquiti UDM-Pro < 5.1.12; Ubiquiti UDM-Pro-Max < 5.1.12; Ubiquiti UDM-SE < 5.1.12; and 4 more.
Is there a fix for CVE-2026-34909?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-34909 attacked?
It is attacked over the network, in an operating system.
Am I affected by CVE-2026-34909?
Check whether you run Ubiquiti EFG, Ubiquiti UDM-Pro, Ubiquiti UDM-Pro-Max or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A path traversal vulnerability (CWE-22) exists in multiple Ubiquiti UniFi OS devices. The flaw allows an unauthenticated attacker with network access to the device to bypass directory restrictions and access sensitive files on the underlying operating system. By manipulating these files, an attacker can escalate privileges or gain unauthorized access to system accounts. The vulnerability is rated critical with a CVSS score of 10.0 due to its potential for full system compromise. Patches have been released for various product lines, including UniFi OS Server (v5.0.8), Express (v4.0.14), and the UDM series (v5.1.12).

Affected products

  • Ubiquiti UniFi OS Server < 5.0.8
  • Ubiquiti Express < 4.0.14
  • Ubiquiti UDM / UDM-Pro / UDM-SE / UDM-Pro-Max / EFG / UDW / UDR / UDR7 / UDR-5G < 5.1.12
  • Ubiquiti UDM-Beast < 5.1.11

Timeline

  • 2026-05-21: disclosed: Initial disclosure by HackerOne
  • 2026-05-21: advisory: NVD Published Date
  • 2026-06-23: other: Advisory publication date provided in report

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