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": "2026-08-26T10:16:42.283Z",
  "pubdate": "2026-08-26T10:16:42.283Z",
  "executiveSummary": "The UniFi Access Application contains an Improper Input Validation vulnerability that permits unauthorized OS command execution.\nThis vulnerability is classified as a Command Injection flaw, posing a critical risk to the confidentiality, integrity, and availability of the host device.\nA malicious actor with network access and low-privileged credentials can leverage this flaw to escape application constraints and execute arbitrary commands with the privileges of the application process.\nThe attack requires prior network connectivity and authenticated, albeit low-privileged, access to the UniFi Access environment.\nSuccessful exploitation allows for complete compromise of the underlying host, potentially leading to unauthorized data access, system disruption, or lateral movement within the network infrastructure.\nOrganizations using UniFi Access are advised to treat this as a high-severity security concern and apply updates immediately upon availability.",
  "technicalDetails": "The root cause of this vulnerability lies in the insufficient sanitization of user-supplied input handled by the UniFi Access Application. When the application processes specific requests, it fails to properly validate or escape input parameters before passing them to system-level calls or shell interpreters.\nThe vulnerability manifests when the application constructs command strings using unsanitized input data. An attacker can inject malicious shell metacharacters—such as semicolons, pipes, or backticks—into the input fields. These characters manipulate the command-line structure, allowing the attacker to terminate the intended command and append arbitrary payloads that the host operating system then executes.\nThe exploitation flow begins with the attacker establishing network access to the target UniFi Access instance. With valid low-privileged credentials, the attacker identifies a vulnerable interface or endpoint within the application that interacts with the backend operating system. By crafting a specifically engineered request containing command injection sequences, the attacker bypasses existing input filters.\nUpon receiving the request, the UniFi Access Application passes the malicious string to the system shell or an OS-level function call without adequate validation. The shell interprets the injected sequences as legitimate commands, leading to their execution with the effective permissions of the UniFi Access service.\nGiven that these applications typically run with elevated permissions to manage access hardware and authentication protocols, the post-exploitation impact is severe. The attacker can execute arbitrary binary code, install persistent backdoors, exfiltrate sensitive configuration files, or perform reconnaissance on the internal network segment. By gaining a command execution foothold, the actor bypasses application-layer security controls entirely, effectively granting them full control over the host device's operating environment."
}