CVE-2026-77535: UniFi Network Application RCE Vulnerability

CVE-2026-77535 Overview

CVE-2026-77535 is a command injection vulnerability in the Ubiquiti UniFi Network Application. The flaw stems from improper input validation [CWE-20] in the workflow that manages adopted devices. An authenticated attacker with high privileges and network access to the application can inject operating system commands that execute on an adopted device. Because the vulnerability crosses a trust boundary between the management application and managed hardware, the scope changes and impacts confidentiality, integrity, and availability of the downstream device.

Critical Impact
An authenticated high-privileged attacker can execute arbitrary commands on adopted UniFi devices, providing a pivot point from the management application into the managed network infrastructure.

Affected Products

Ubiquiti UniFi Network Application
Adopted UniFi devices managed by the application
See the UI Security Advisory Bulletin 067 for exact fixed versions

Discovery Timeline

2026-08-26 - CVE-2026-77535 published to the National Vulnerability Database (NVD)
2026-08-26 - Last updated in NVD database

Technical Details for CVE-2026-77535

Vulnerability Analysis

The UniFi Network Application centrally manages Ubiquiti network devices through an adoption and provisioning workflow. CVE-2026-77535 exists because input handled by this workflow is not properly validated before being incorporated into commands executed on adopted devices. An attacker with high-privileged access to the application supplies crafted input that breaks out of the intended command context and runs attacker-controlled OS commands on the target device.

The vulnerability changes trust scope. Exploitation begins inside the management application but results in code execution on a separate managed device. This allows lateral movement from the controller plane to switches, access points, gateways, or other adopted infrastructure.

Root Cause

The root cause is improper input validation [CWE-20]. The application accepts input from a privileged user context and passes it into a command-execution path targeting adopted devices without sufficient sanitization or safe API construction. The affected code trusts operator-supplied values that should be treated as untrusted data.

Attack Vector

Exploitation requires network reachability to the UniFi Network Application and an account with high privileges. No user interaction is required. The attacker submits crafted values through a management interface that reaches the vulnerable input handling logic, and the resulting command runs on the adopted device with the privileges assigned to the management channel.

No verified public proof-of-concept code is available. Technical detail on the vulnerable component is described in prose only. Refer to the UI Security Advisory Bulletin 067 for vendor-supplied information.

Detection Methods for CVE-2026-77535

Indicators of Compromise

Unexpected shell processes or command interpreters launched on adopted UniFi devices outside normal provisioning windows.
Configuration changes on adopted devices that do not correspond to a legitimate administrator action in the UniFi Network Application audit log.
Outbound connections from adopted devices to unfamiliar destinations following administrative activity on the controller.

Detection Strategies

Correlate UniFi Network Application administrative actions with device-side syslog to identify commands that lack a matching controller-side workflow.
Alert on anomalous input in adoption, provisioning, or device-configuration API calls, particularly values containing shell metacharacters.
Monitor high-privileged account usage within the UniFi Network Application for logins from unusual sources or off-hours activity.

Monitoring Recommendations

Forward UniFi Network Application logs and adopted device syslog to a centralized SIEM for correlation and retention.
Baseline normal administrator behavior and alert on deviations such as bulk configuration pushes or unusual command patterns.
Track privilege assignments in the UniFi Network Application and alert when accounts are elevated to super-admin roles.

How to Mitigate CVE-2026-77535

Immediate Actions Required

Upgrade the UniFi Network Application to the fixed release identified in UI Security Advisory Bulletin 067.
Audit all accounts that hold high-privileged roles in the UniFi Network Application and remove unnecessary privilege.
Rotate credentials for administrative accounts and review recent audit logs for suspicious activity.

Patch Information

Ubiquiti published fix guidance in Security Advisory Bulletin 067. Administrators should apply the vendor-supplied update to the UniFi Network Application and verify that adopted devices report the expected firmware and configuration state after upgrade. Consult the vendor advisory for exact fixed version numbers.

Workarounds

Restrict network access to the UniFi Network Application management interface using firewall rules and management VLANs.
Enforce multi-factor authentication on all administrative accounts to raise the cost of privileged credential abuse.
Reduce the number of accounts with the highest privilege tier and apply least-privilege role assignments.

bash

# Example: restrict management access to a trusted admin subnet (iptables)
iptables -A INPUT -p tcp --dport 8443 -s 10.10.20.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 8443 -j DROP