CVE-2026-34909 CRITICAL

CVE-2026-34909

Vendor Ubiquiti Inc
Product UniFi OS Server
Weakness CWE-22 · Path traversal
KEV Status Known Exploited
Published May 22, 2026
Last update May 22, 2026
View on NVD All CVEs

CVSS base score

10.0/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

What the vulnerability does

01Description

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.

CISA mandated remediation

02CISA 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.

Key dates

03Disclosure timeline

May 22, 2026 CVE published
May 22, 2026 Record updated

External resources

04References

NVD — National Vulnerability Database https://nvd.nist.gov/vuln/detail/CVE-2026-34909 CWE — Common Weakness Enumeration https://cwe.mitre.org/data/definitions/22.html CISA KEV Reference https://community.ui.com/releases/Security-Advisory-Bulletin-0… CISA KEV Reference https://www.cisa.gov/news-events/directives/bod-26-04-prioriti… CISA KEV Reference https://www.cisa.gov/news-events/directives/bod-26-04-implemen… CISA KEV Reference https://nvd.nist.gov/vuln/detail/CVE-2026-34909