CVE-2026-34909
CWE-22Published: May 22, 2026· Updated: May 22, 2026
Official 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.
Risk Analysis
This critical vulnerability in UniFi OS devices allows a malicious actor with network access to traverse directories and access sensitive files. The flaw is a path traversal vulnerability that can lead to unauthorized account access. With a perfect CVSS score of 10.0, this vulnerability poses an extreme risk of data and system compromise.
This vulnerability is actively exploited in the wild and is listed in CISA's KEV catalog. Attackers can exploit this remotely without authentication due to the network attack vector and low attack complexity.
Apply all available security updates for UniFi OS devices. Implement strict access controls and ensure proper input sanitization to prevent path traversal attacks.
Technical Analysis
CVE-2026-34909 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 10.0.
The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.
CISA has added CVE-2026-34909 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
CVSS v3.1 Vector Breakdown
Exploit & PoC Resources
News & Research Mentioning CVE-2026-34909
CISA has added four new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog, based on evidence of active exploitation. CVE-2025-67038 Lantronix EDS5000 Code Injection Vulnerability CVE-2026-34908 Ubiquiti UniFi OS Improper Access Control Vulnerability CVE-2026-34909 Ubiquiti UniFi OS Path Traversal Vulnerability CVE-2026-34910 Ubiquiti UniFi OS Improper Input Validation Vulnerability These types of vulnerabilities are frequent attack vectors for malicious cyber actors and pose significant risks to the federal enterprise. Binding Operational Directive (BOD) 26-04: Prioritizing Security Updates Based on Risk establishes vulnerability management requirements for Federal Civilian Executive Branch (FCEB) agencies. BOD 26-04 reinforces the [xlite_meta score:57 src:CISA Alerts xlite_fp:37fb12cf2f470b964b3221878929f6fbe87847a31c1780ce770396252a833570]
All References (1)
Quick Facts
Related CVEs (CWE-22)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-34909 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1