Cyber Resilience

CVE-2026-34911

Path Traversal in Ui Unifi Os Server ≤ 5.0.8

Published
22 May 2026
Modified
23 July 2026
Patch / advisory
CVSS Score v3.1 7.7
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
EPSS Score 0.0068 49th percentile
Risk Priority 56 floored blend · peak EPSS

Summary

CVE-2026-34911 is a high-severity Path Traversal (CWE-22) vulnerability in Ui Unifi Os Server. Its CVSS base score is 7.7 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 49th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A malicious actor with access to the network and low privileges could exploit a Path Traversal vulnerability found in UniFi OS devices to access files on the underlying system that could be manipulated to obtain sensitive information.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-34909Same product: Ui Enterprise Fortress Gateway
CVE-2015-9266Same vendor: Ui
CVE-2025-21048Shared CWE-22
CVE-2026-23939Shared CWE-22
CVE-2024-7145Shared CWE-22
CVE-2023-42225Shared CWE-22
CVE-2024-33109Shared CWE-22
CVE-2023-35016Shared CWE-22
CVE-2025-10723Shared CWE-22
CVE-2023-1163Shared CWE-22

Affected Assets

ui
unifi os server
≤ 5.0.8
ui
unifi cloud gateway industrial firmware
≤ 5.1.12
ui
unifi dream machine firmware
≤ 5.1.12
ui
unifi dream machine pro firmware
≤ 5.1.12
ui
unifi dream machine special edition firmware
≤ 5.1.12
ui
unifi dream machine pro max firmware
≤ 5.1.12
ui
enterprise fortress gateway firmware
≤ 5.1.12
ui
unifi dream wall firmware
≤ 5.1.12
ui
unifi dream router firmware
≤ 5.1.12
ui
unifi dream router 7 firmware
≤ 5.1.12
+21 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V5.3.2

Mitigating Controls (NIST 800-53 r5) AI

Enforces the intended directory access authorizations that path traversal would otherwise bypass.

Input validation directly neutralizes special path elements before pathname construction occurs.

Least privilege reduces the impact of any unauthorized file access obtained via traversal.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-02 partial match
prevents

Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.

PR.AA-05 none match
prevents

PR.AA-05 defines and reviews access policies but does not address code-level pathname neutralization, so neither direction prevents CWE-22.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development catches path traversal via static/dynamic analysis.

prevents

Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.

prevents

Application security requirements include rules for safe file handling and canonicalization.

prevents

Secure architecture principles require least-privilege file access and directory isolation.

prevents

Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.

mitigates

Information access restriction limits which files an application may read or write.

References