🔴 CVE-2026-34909

CVE-2026-34909 is a critical (CVSS 10.0) unauthenticated path traversal vulnerability in Ubiquiti UniFi OS devices (UDM, UDM-Pro, UDM-SE, UniFi OS Server, Express, and related gateway/NVR/storage devices) that allows an attacker with network access to read arbitrary system files and escalate to account takeover. The flaw is remotely exploitable with no authentication or user interaction, is actively exploited in the wild, and is listed in CISA's KEV catalog, making it a textbook T1190 case.

← Back to Overview
HIGH_RISK
Risk Level
10.0
CVSS Score
NETWORK
Attack Vector
Initial Access
ATT&CK Tactic
T1190 — Exploit Public-Facing Application
ATT&CK Technique
HIGH
Deployment Risk
No
Ransomware

📋 Vulnerability Details

Data Source: CIRCL

Confidence: HIGH

Exploitation Method: DIRECT_NETWORK

CVE Published: 2026-05-22

Added to CISA KEV: 2026-06-23 32 DAYS BETWEEN CVE AND KEV

🎯 Recommendations:

🔍 Web Intelligence (Kagi · 2026-09-14)

Summary

CVE-2026-34909 is a critical path traversal vulnerability (CVSS score of 10.0) affecting Ubiquiti UniFi OS devices. The vulnerability allows an unauthorized attacker with network access to the device to supply specially crafted path sequences that escape the intended directory, enabling them to read arbitrary files on the underlying system. This capability can subsequently be leveraged to manipulate system files or configurations, ultimately resulting in unauthorized access to an underlying account on the affected device [1][2].

Exploitation

  • Active Exploitation: The vulnerability is listed in CISA's Known Exploited Vulnerabilities (KEV) Catalog, indicating active exploitation in the wild [1].
  • Threat Actors/Campaigns: Specific threat actors or named ransomware campaigns associated with this vulnerability have not been publicly disclosed.
  • Proof-of-Concept/Exploit Availability: While the vulnerability is considered critical and is being actively exploited, there are no widely available public proof-of-concept exploits [4].
  • Attack Prerequisites: The attack can be initiated remotely by an actor with network access to the target device. No authentication is required to initiate the traversal, and no specific user interaction is needed [2][4].

Affected Products & Patches

  • Affected Products: Ubiquiti UniFi OS devices are the primary component affected [1].
  • Patches: Users are advised to check for and apply firmware updates immediately; verify official Ubiquiti security advisories for the specific patch version corresponding to your hardware [5].
  • Mitigations: In instances where a patch cannot be immediately applied, it is recommended to restrict network access to the management interface. Additionally, disable or remove any file-system browsing or management features that expose the host filesystem through the web interface, and monitor system logs for anomalous file access patterns or path traversal attempts [3].

Impact

  • System Access: Successful exploitation provides attackers the ability to read arbitrary files, which facilitates further manipulation of the system, ultimately leading to unauthorized account takeover [2][5].
  • Business Risk: For internet-facing deployments, this vulnerability presents a severe risk as it allows remote, unauthenticated actors to gain full control over the network infrastructure device, potentially leading to unauthorized network access, data interception, or the establishment of a persistent foothold within the organization's network.

Sources

  1. CVE-2026-34909 Detail - NVD

    Description. A malicious actor with access to the network could exploit a Path Traversal vulnerability found in UniFi OS devices to access ... CVE-2026-34909 Detail. Description. A malicious actor with access to the network could exploit a Path Traversal vulnerability found in UniFi OS devices to ac…

  2. CVE-2026-34909 - Ubiquiti UniFi OS Path Traversal Vulnerability

    CVE-2026-34909 is a CRITICAL path traversal vulnerability in Ubiquiti UniFi OS, carrying the maximum CVSS 3.1 score of 10.0. The flaw lets a malicious actor with network access to a UniFi OS device supply crafted path sequences that escape the intended directory and read files on the underlying syst…

  3. CVE-2026-34909 - Vulnerability Details - OpenCVE

    Where possible, disable or remove any file‑system browsing or file management features that expose the host filesystem through the web interface Monitor system logs for attempts to perform path traversal or anomalous file access patterns Generated by OpenCVE AI on August 10, 2026 at 23:46 UTC.

  4. CVE-2026-34909 - Exploits & Severity - Feedly

    CVE-2026-34909 is a critical Path Traversal vulnerability in UniFi OS devices, with a CVSS score of 10, allowing attackers with network access to traverse the file system and manipulate sensitive files to gain account access. Currently, there are no public proof-of-concept exploits, patches, or miti…

  5. CVE-2026-34909 | Ubiquiti UniFi OS Vulnerability | UpGuard

    CVE-2026-34909 is a critical CVSS 10 path traversal vulnerability in Ubiquiti UniFi OS allowing account takeover. Update firmware immediately.

Generated by PatchNow Intelligence System

Analysis based on CIRCL.LU data, Claude AI assessment, and MITRE ATT&CK framework

📄 Download JSON Data | 📡 RSS Feed