CVERadar
CRITICAL · CVSS 3.1 10CISA KEV · added 2026-06-23EPSS 1.79% (p78)Threat level 66

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

Ubiquiti · UniFi OS · NVD published 2026-05-22 · posted 2026-06-23 · last modified 2026-07-23

What it is

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.

WeaknessCWE-22
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (source: [email protected])
CISA due date2026-06-26 (for US federal agencies under BOD; a good deadline for everyone)
ATT&CK tacticsInitial Access → Discovery

Exploitation evidence

First exploit evidence seen: 2026-06-23 (earliest date across the sources below).

Exploited in the wild

  • CISA KEV: listed since 2026-06-23. Source

Sources: CISA KEV.

Defend the Chain

The attack chain for CVE-2026-34909 laid across the MITRE ATT&CK Enterprise tactics. Solid cards come from the MITRE CTID KEV mappings; dashed cards are inferred by CVERadar from the CWE or description. Correct defences are real ATT&CK mitigations for that technique.

Threat level 66/100
Defender level 1 · 0 XP
Chain links broken: 0/2

Reconnaissance

Resource Development

Initial Access

Execution

Persistence

Privilege Escalation

Stealth

Defense Impairment

Credential Access

Discovery

Lateral Movement

Collection

Command and Control

Exfiltration

Impact

Pick a red technique card on the board, then choose the defence that stops it.

Defend against T1190 Exploit Public-Facing Application Inferred

Inferred from CWE CWE-22

How to fix it

CISA required action

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. (source: CISA KEV)

Fixed versions

  • ui unifi os server: upgrade to 5.0.8 or later
  • ui unifi cloud gateway industrial firmware: upgrade to 5.1.12 or later
  • ui unifi dream machine firmware: upgrade to 5.1.12 or later
  • ui unifi dream machine pro firmware: upgrade to 5.1.12 or later
  • ui unifi dream machine special edition firmware: upgrade to 5.1.12 or later
  • ui unifi dream machine pro max firmware: upgrade to 5.1.12 or later
  • ui enterprise fortress gateway firmware: upgrade to 5.1.12 or later
  • ui unifi dream wall firmware: upgrade to 5.1.12 or later
  • ui unifi dream router firmware: upgrade to 5.1.12 or later
  • ui unifi dream router 7 firmware: upgrade to 5.1.12 or later
  • ui unifi express 7 firmware: upgrade to 5.1.12 or later
  • ui unifi network video recorder firmware: upgrade to 5.1.12 or later
  • ui unifi network video recorder pro firmware: upgrade to 5.1.12 or later
  • ui unifi network video recorder instant firmware: upgrade to 5.1.12 or later
  • ui enterprise network video recorder firmware: upgrade to 5.1.12 or later
  • ui unifi cloud gateway ultra firmware: upgrade to 5.1.12 or later
  • ui unifi cloud gateway max firmware: upgrade to 5.1.12 or later
  • ui unifi cloud gateway fiber firmware: upgrade to 5.1.12 or later
  • ui unifi dream router 5g max firmware: upgrade to 5.1.12 or later
  • ui enterprise network video recorder core firmware: upgrade to 5.1.12 or later
  • ui unifi cloud key plus firmware: upgrade to 5.1.12 or later
  • ui unifi cloudkey firmware: upgrade to 5.1.12 or later
  • ui unifi cloudkey enterprise firmware: upgrade to 5.1.12 or later
  • ui unifi network video recorder g2 firmware: upgrade to 5.1.12 or later
  • ui unifi network video recorder g2 pro firmware: upgrade to 5.1.12 or later

Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.

Vendor advisories and patches

MITRE ATT&CK mitigations for this chain

  • M1048 Application Isolation and Sandboxing (for T1190) : Application isolation will limit what other processes and system features the exploited target can access.
  • M1037 Filter Network Traffic (for T1190) : Restrict outbound network traffic from public-facing servers to prevent unauthorized connections from initiating communications with attacker-controlled infrastructure. While this may not prevent the initial exploitation, it limits the attacker's ability to verify and control the compromised server post-exploit, reduci
  • M1030 Network Segmentation (for T1190) : Segment externally facing servers and services from the rest of the network with a DMZ or on separate hosting infrastructure.
  • M1016 Vulnerability Scanning (for T1190) : Regularly scan externally facing systems for vulnerabilities and establish procedures to rapidly patch systems when critical vulnerabilities are discovered through scanning and through public disclosure.
  • M1026 Privileged Account Management (for T1190) : Use least privilege for service accounts will limit what permissions the exploited process gets on the rest of the system.
  • M1050 Exploit Protection (for T1190) : Web Application Firewalls may be used to limit exposure of applications to prevent exploit traffic from reaching the application.
  • M1035 Limit Access to Resource Over Network (for T1190) : Ensure that all publicly exposed services are actually intended to be so, and restrict access to any that should only be available internally.
  • M1051 Update Software (for T1190) : Update software regularly by employing patch management for externally exposed applications.

Detection Generic guidance

  • Initial Access: Alert on unusual requests to the affected service (odd paths, oversized payloads, exploit strings) in WAF, reverse-proxy and application logs.
  • Discovery: Look for directory listing, file enumeration and reconnaissance commands from service accounts.

Response checklist Generic guidance

  1. Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
  2. Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
  3. Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
  4. Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.

Sources