CVE-2026-34908UbiquitiRouters and networkingJune 23, 2026

Ubiquiti UniFi OS Improper Access Control Vulnerability

Critical 10Actively exploited

Description

Ubiquiti UniFi OS contains an improper access control vulnerability which could allow a malicious actor with access to the network to make unauthorized changes to the system.

What to do

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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Details

Vendor
Ubiquiti
Product
UniFi OS
CVE
CVE-2026-34908
Affected versions
UniFi OS Server 5.0: before 5.0.8 — fixed in 5.0.8
UDM 5.1: before 5.1.12 — fixed in 5.1.12
UDM-Pro 5.1: before 5.1.12 — fixed in 5.1.12
UDM-SE 5.1: before 5.1.12 — fixed in 5.1.12
UDM-Pro-Max 5.1: before 5.1.12 — fixed in 5.1.12
UDM-Beast 5.1: before 5.1.11 — fixed in 5.1.11
EFG 5.1: before 5.1.12 — fixed in 5.1.12
UDW 5.1: before 5.1.12 — fixed in 5.1.12
UDR 5.1: before 5.1.12 — fixed in 5.1.12
UDR7 5.1: before 5.1.12 — fixed in 5.1.12
UDR-5G 5.1: before 5.1.12 — fixed in 5.1.12
Express 7 5.1: before 5.1.12 — fixed in 5.1.12
UNVR 5.1: before 5.1.12 — fixed in 5.1.12
UNVR-Pro 5.1: before 5.1.12 — fixed in 5.1.12
UNVR-Instant 5.1: before 5.1.12 — fixed in 5.1.12
UNVR-G2 5.1: before 5.1.12 — fixed in 5.1.12
UNVR-G2-Pro 5.1: before 5.1.12 — fixed in 5.1.12
ENVR 5.1: before 5.1.12 — fixed in 5.1.12
ENVR-Core 5.1: before 5.1.12 — fixed in 5.1.12
UNAS-2 5.1: before 5.1.10 — fixed in 5.1.10
UNAS-4 5.1: before 5.1.10 — fixed in 5.1.10
UNAS-Pro 5.1: before 5.1.10 — fixed in 5.1.10
UNAS-Pro-4 5.1: before 5.1.10 — fixed in 5.1.10
UNAS-Pro-8 5.1: before 5.1.10 — fixed in 5.1.10
UCKP 5.1: before 5.1.12 — fixed in 5.1.12
UCK 5.1: before 5.1.12 — fixed in 5.1.12
UCK-Enterprise 5.1: before 5.1.12 — fixed in 5.1.12
UCG-Ultra 5.1: before 5.1.12 — fixed in 5.1.12
UCG-Max 5.1: before 5.1.12 — fixed in 5.1.12
UCG-Fiber 5.1: before 5.1.12 — fixed in 5.1.12 (from the advisory and NVD; check the exact builds in the official advisory)
CVSS score
10
Actively exploited
Yes, listed in the CISA Known Exploited Vulnerabilities catalog
CISA due date
June 26, 2026 (deadline for US federal agencies: a good benchmark for you too)
Source
CISA KEV – original advisory
Published
June 23, 2026

The description and the recommended action are quoted from the public advisory; severity, exploitation status and affected versions are compiled automatically from public sources and may contain errors. The vendor's original advisory prevails: check it before taking action. This information is provided without warranty and does not replace a professional assessment.

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