Description

A malicious actor with access to the network and low privileges could exploit an Improper Input Validation vulnerability found in UniFi Access Application to execute a Command Injection on the host device.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.9",
  "pubDate": "2026-08-26T11:16:38.573Z",
  "pubdate": "2026-08-26T11:16:38.573Z",
  "executiveSummary": "The UniFi Access Application is susceptible to an Improper Input Validation vulnerability that facilitates remote Command Injection.\nThis vulnerability allows an attacker with low-privileged network access to execute arbitrary system commands on the underlying host device.\nThe flaw originates from the application's failure to adequately sanitize user-supplied data before passing it to system-level execution functions.\nSuccessful exploitation poses a critical risk to the confidentiality, integrity, and availability of the host device, potentially granting the attacker full system control.\nThe attack is characterized as a post-authentication exploit, requiring the adversary to have existing network access and low-level application privileges.\nGiven the nature of Command Injection, this vulnerability could be leveraged to bypass security controls, escalate privileges, or establish persistent unauthorized access within the managed network environment.",
  "technicalDetails": "The vulnerability is rooted in an Improper Input Validation flaw within the UniFi Access Application, which functions as an entry point for administrative or control tasks. The application fails to enforce strict validation or sanitization routines on input parameters provided by a user before these inputs are processed by system shell commands.\nExploitation involves the injection of malicious shell metacharacters into input fields that are subsequently evaluated by the underlying operating system. By manipulating these parameters, an attacker can break out of the intended application context and force the execution of arbitrary commands with the permissions of the user running the UniFi Access Application service.\nThe attack flow proceeds as follows: First, the attacker, possessing legitimate low-level network access, interacts with the application’s interface or API. Second, the attacker submits a specifically crafted payload containing shell commands (e.g., using command separators like ';', '|', or '&&'). Third, the application's backend component receives this unvalidated input and passes it directly to a system call, such as popen() or system(). Fourth, the operating system executes the malicious payload, enabling the attacker to run system binaries or scripts.\nBecause the UniFi Access Application requires interaction with the host hardware, the service often operates with elevated privileges, typically root or a high-level service account. Consequently, the Command Injection primitive permits the attacker to achieve full host compromise, including access to sensitive system files, configuration data, and network traffic interception capabilities.\nThe vulnerability is constrained by the necessity of network-level access, meaning the attacker must be capable of reaching the application port. However, once network reachability is established, no further interaction is required to trigger the command execution. The technical severity is high, as the lack of robust input filtering allows for straightforward exploitation techniques to bypass existing security boundaries. Remediation requires the implementation of parameterized interfaces, the enforcement of allow-lists for user input, and the transition away from system-level command execution where possible."
}