CVE-2026-77547 in Access Application
Summary
by MITRE • 08/26/2026
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.
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Analysis
by VulDB Data Team • 08/26/2026
The discovery of a command injection vulnerability within the UniFi Access application represents a significant security risk for organizations relying on this platform for physical access control management. This flaw stems from improper input validation, specifically where user-supplied data is not adequately sanitized before being processed by underlying system commands. In typical operational scenarios, an attacker who has gained network access and possesses low-level privileges can leverage this weakness to inject arbitrary operating system commands into the application's execution flow. The severity of this vulnerability lies in its potential for privilege escalation; while initial access may be limited, successful exploitation allows the adversary to execute code with the same permissions as the UniFi Access service account, which often runs with elevated rights on the host device hosting the management software.
From a technical perspective, command injection vulnerabilities occur when an application passes unsafe user input to a system shell or interpreter without proper escaping or validation. In the context of UniFi Access, this likely involves endpoints that handle configuration changes, log queries, or integration parameters where special characters such as semicolons, pipes, or ampersands are not filtered out. When these characters reach the backend command execution layer, they can terminate the intended command and initiate a new one defined by the attacker. This mechanism bypasses standard application-level security controls because the operating system interprets the injected string as legitimate executable code rather than malicious data. The lack of strict input validation creates an attack vector that is both reliable and difficult to detect through conventional monitoring tools, especially if the executed commands are designed to be stealthy or mimic normal administrative activity.
The operational impact of this vulnerability extends beyond simple unauthorized access. An attacker exploiting command injection can compromise the integrity and availability of the entire physical security infrastructure. By executing arbitrary commands on the host device, an adversary could modify access control policies, disable logging mechanisms to cover their tracks, exfiltrate sensitive data such as credential databases or user logs, or even pivot further into the internal network by using the compromised server as a foothold. In critical environments where UniFi Access manages entry points for high-security areas, this capability allows an attacker to physically bypass security measures without triggering alarms if logging is disabled. Furthermore, the compromise of the management host can lead to broader network infiltration, affecting other connected systems and potentially leading to data breaches or ransomware deployment across the organization's IT assets.
To mitigate these risks, organizations must implement a multi-layered defense strategy aligned with industry standards such as CWE-78 for Improper Neutralization of Special Elements used in an OS Command and MITRE ATT&CK technique T1059 for Command and Scripting Interpreter abuse. Immediate remediation involves applying the latest security patches provided by Ubiquiti, which address the input validation flaws within specific versions of the UniFi Access application. In addition to patching, administrators should enforce strict network segmentation to limit lateral movement from compromised endpoints to critical infrastructure servers. Implementing Web Application Firewalls with rules specifically tuned for command injection patterns can provide an additional layer of detection and prevention. Regular vulnerability assessments and penetration testing focused on input validation weaknesses are essential to identify similar flaws before they can be exploited by malicious actors seeking to compromise physical security systems.