CVE-2026-34909

Ubiquiti UniFi OS path traversal, confirmed exploited in the wild.

Ubiquiti UniFi OS contains a path traversal vulnerability which could allow a malicious actor with access to the network to access files on the underlying system that could be manipulated to access an underlying account.

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69%chance of exploitation in the next 30 days (EPSS), 99th percentile

23 Junadded to CISA's Known Exploited Vulnerabilities list, 2026

26 Junfederal remediation deadline, already passed

Passedpast the deadline: patch now

CISA's name for it	Ubiquiti UniFi OS Path Traversal Vulnerability
Vendor and product	Ubiquiti · UniFi OS
Type	path traversal · CWE-22
Exploited	Confirmed by CISA listed 23 June 2026
Likelihood	one of the most likely to be exploited of every vulnerability tracked
Deadline	26 June 2026 · already passed
Used in ransomware	Not reported
Advisories	community.ui.com ↗ · www.cisa.gov ↗ · www.cisa.gov ↗ · nvd.nist.gov ↗

What to do

Three steps, in this order

Step 1

Apply the vendor fix.

Step 2

Assume files readable through the flaw were read: rotate secrets and keys stored on the system.

Step 3

Restrict access to the interface until patched.

CISA's 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.

CISA's 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.

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Questions

CVE-2026-34909 in short

Is CVE-2026-34909 being exploited?

Yes. CISA added CVE-2026-34909 to its Known Exploited Vulnerabilities catalogue on 23 June 2026, which it does only on evidence of exploitation in the wild.

What is the CISA deadline for CVE-2026-34909?

US federal agencies must remediate it by 26 June 2026. Everyone else should treat that date as the latest safe point to patch an internet-facing system.

How likely is CVE-2026-34909 to be exploited in the next 30 days?

FIRST's Exploit Prediction Scoring System gives it 69%, the 99th percentile of every CVE it scores.

How do I fix CVE-2026-34909?

Apply the vendor fix. Assume files readable through the flaw were read: rotate secrets and keys stored on the system. Restrict access to the interface until patched.

Same vendor

Other Ubiquiti vulnerabilities being exploited

CVE	Product	Type	Listed
CVE-2026-34910	UniFi OS	command injection	23 June 2026
CVE-2026-34908	UniFi OS	exploited vulnerability	23 June 2026

Sources: CISA Known Exploited Vulnerabilities catalogue (released 10 November 2026) and FIRST EPSS. Page compiled automatically by SAK T.L.M, the threat-intelligence tool of SAK T.E.C, on 13 November 2026.