CVEs / CVE-2026-34909
CVE-2026-34909: Ubiquiti UniFi OS Path Traversal Vulnerability
- Known exploited in the CISA KEV catalog since 23 Jun 2026
- critical 10 CVSS 3.1 (from the CNA)
- EPSS 68% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
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.
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Ubiquiti Inc UniFi OS Server | before 5.0.8 | 5.0.8 |
| Ubiquiti Inc Express | before 4.0.14 | 4.0.14 |
| Ubiquiti Inc UDM | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UDM-Pro | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UDM-SE | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UDM-Pro-Max | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UDM-Beast | before 5.1.11 | 5.1.11 |
| Ubiquiti Inc EFG | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UDW | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UDR | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UDR7 | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UDR-5G | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc Express 7 | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UNVR | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UNVR-Pro | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UNVR-Instant | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UNVR-G2 | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UNVR-G2-Pro | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc ENVR | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc ENVR-Core | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UNAS-2 | before 5.1.10 | 5.1.10 |
| Ubiquiti Inc UNAS-4 | before 5.1.10 | 5.1.10 |
| Ubiquiti Inc UNAS-Pro | before 5.1.10 | 5.1.10 |
| Ubiquiti Inc UNAS-Pro-4 | before 5.1.10 | 5.1.10 |
| Ubiquiti Inc UNAS-Pro-8 | before 5.1.10 | 5.1.10 |
| Ubiquiti Inc UCKP | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UCK | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UCK-Enterprise | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UCG-Ultra | before 5.1.12 | 5.1.12 |
| Ubiquiti Inc UCG-Max | before 5.1.12 | 5.1.12 |
Exploitation
| In CISA KEV since | 23 Jun 2026 |
|---|---|
| Due date for US federal agencies | 26 Jun 2026 |
| Used in ransomware campaigns | Unknown |
| 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. |
Severity
| CVSS 3.1 | 10 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-22 |
References
- CVE-2026-34909 on NVD
- CVE-2026-34909 in the CISA KEV catalog
- https://community.ui.com/releases/Security-Advisory-Bulletin-064-064/84811c09-4cf4-42ab-bd61-cc994445963b (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk (cited by CISA)
- https://community.ui.com/releases/Security-Advisory-Bulletin-064-064/84811c09-4cf4-42ab-bd61-cc994445963b Patch, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-34909 US Government Resource
- https://www.pwndefend.com/2026/06/09/cve-2026-34910-exploitation-itw-building-a-botnet-mirai/ Exploit, Third Party Advisory
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.