Actively exploited · Published May 22, 2026 · Assigned by hackerone
CVE-2026-34909
Critical 10.0 Exploited
In plain English
A critical-severity path traversal in EFG from Ubiquiti Inc. Attackers are actively exploiting it in the wild (listed by CISA on June 23, 2026). The chance it is exploited in the next 30 days is estimated at 69.2% (higher than 99.4% of all known vulnerabilities). 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 guidance
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.
Federal agencies must remediate by Jun 26, 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Ubiquiti Inc | UniFi OS Server | 0 – before 5.0.8 |
| Ubiquiti Inc | Express | 0 – before 4.0.14 |
| Ubiquiti Inc | UDM | 0 – before 5.1.12 |
| Ubiquiti Inc | UDM-Pro | 0 – before 5.1.12 |
| Ubiquiti Inc | UDM-SE | 0 – before 5.1.12 |
| Ubiquiti Inc | UDM-Pro-Max | 0 – before 5.1.12 |
| Ubiquiti Inc | UDM-Beast | 0 – before 5.1.11 |
| Ubiquiti Inc | EFG | 0 – before 5.1.12 |
| Ubiquiti Inc | UDW | 0 – before 5.1.12 |
| Ubiquiti Inc | UDR | 0 – before 5.1.12 |
| Ubiquiti Inc | UDR7 | 0 – before 5.1.12 |
| Ubiquiti Inc | UDR-5G | 0 – before 5.1.12 |
| Ubiquiti Inc | Express 7 | 0 – before 5.1.12 |
| Ubiquiti Inc | UNVR | 0 – before 5.1.12 |
| Ubiquiti Inc | UNVR-Pro | 0 – before 5.1.12 |
| Ubiquiti Inc | UNVR-Instant | 0 – before 5.1.12 |
| Ubiquiti Inc | UNVR-G2 | 0 – before 5.1.12 |
| Ubiquiti Inc | UNVR-G2-Pro | 0 – before 5.1.12 |
| Ubiquiti Inc | ENVR | 0 – before 5.1.12 |
| Ubiquiti Inc | ENVR-Core | 0 – before 5.1.12 |
| Ubiquiti Inc | UNAS-2 | 0 – before 5.1.10 |
| Ubiquiti Inc | UNAS-4 | 0 – before 5.1.10 |
| Ubiquiti Inc | UNAS-Pro | 0 – before 5.1.10 |
| Ubiquiti Inc | UNAS-Pro-4 | 0 – before 5.1.10 |
| Ubiquiti Inc | UNAS-Pro-8 | 0 – before 5.1.10 |
| Ubiquiti Inc | UCKP | 0 – before 5.1.12 |
| Ubiquiti Inc | UCK | 0 – before 5.1.12 |
| Ubiquiti Inc | UCK-Enterprise | 0 – before 5.1.12 |
| Ubiquiti Inc | UCG-Ultra | 0 – before 5.1.12 |
| Ubiquiti Inc | UCG-Max | 0 – before 5.1.12 |
Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
References
- https://community.ui.com/releases/Security-Advisory-Bulletin-064-064/84811c09-4cf4-42ab-bd61-cc994445963b
- https://www.pwndefend.com/2026/06/09/cve-2026-34910-exploitation-itw-building-a-botnet-mirai/ third-party-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-34909 government-resource