CVE-2026-47370: A malicious actor with access to the network and low privileges could exploit an Improper Input Validation vulnerability found in certain devices running UniFi OS to execute a Command Injection within such UniFi OS devices or instances

Synopsis

A command injection vulnerability caused by improper input validation affects multiple Ubiquiti devices running UniFi OS, including the UniFi OS Server, UDM, UDM-Pro, UDM-SE, UDM-Pro-Max, UDM-Beast, EFG, and Express. The vulnerability is reachable over the network by an attacker holding any low-privilege account, with no victim interaction required, and carries a CVSS 9.9 critical score due to its scope-changing impact. Successful exploitation gives the attacker arbitrary command execution on the affected device, with full read, write, and availability impact extending beyond the vulnerable component. Patched-image rebuilds at versions 4.0.15 and 5.1.15 are available on HarborGuard for environments running affected versions.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The attacker must reach the UniFi OS management interface over the network; the service must be exposed to the attacker's network segment.

• AuthenticationRequired

  Any low-privilege account on the device is sufficient; no administrative or elevated credentials are needed beyond basic login access.

• Victim interactionNot required

  No action from a logged-in user or administrator is required to trigger the vulnerability.

• Attack complexityDetail

  Attack complexity is low, meaning the exploit is reliable and does not depend on race conditions, specific memory layouts, or other environmental factors.

Blast Radius

• The attacker executes arbitrary operating system commands on the affected UniFi OS device with the privileges of the vulnerable process.
• Confidential data stored on the device, including network configuration, credentials, and logs, is fully readable.
• The attacker can modify or delete persisted configuration data, potentially altering network routing, firewall rules, or access controls.
• The scope change (S:C) means impact can extend beyond the UniFi OS instance itself to other systems on the managed network that trust the device.