CVE-2026-2182: Utt 521g Firmware RCE Vulnerability

CVE-2026-2182 Overview

A command injection vulnerability has been identified in UTT 进取 521G router firmware version 3.1.1-190816. The vulnerability exists in the doSystem function within the /goform/setSysAdm endpoint, where improper handling of the passwd1 argument allows attackers to inject and execute arbitrary system commands. This flaw enables remote attackers with administrative access to compromise the affected device and potentially gain full control over the router.

Critical Impact

Remote attackers can execute arbitrary commands on the affected UTT 521G router through the administrative interface, potentially leading to complete device compromise, network traffic interception, and lateral movement within the network.

Affected Products

• UTT 521G Firmware version 3.1.1-190816
• UTT 521G Hardware version 2.0

Discovery Timeline

• 2026-02-08 - CVE-2026-2182 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2026-2182

Vulnerability Analysis

This vulnerability is classified as CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component), commonly known as injection. The flaw resides in the doSystem function that processes user-supplied input from the /goform/setSysAdm endpoint without adequate sanitization.

When an authenticated administrator submits a request to change system settings, the passwd1 parameter value is passed directly to a system command execution function. The lack of input validation allows specially crafted payloads containing shell metacharacters to break out of the intended command context and execute attacker-controlled commands with the privileges of the router's web service process.

The network-accessible nature of the vulnerability means that any attacker who has obtained administrative credentials—whether through credential theft, default password exploitation, or session hijacking—can remotely execute commands on the target device.

Root Cause

The root cause of this vulnerability is the failure to properly sanitize user input before passing it to system command execution functions. The doSystem function accepts the passwd1 argument directly from HTTP form data and incorporates it into a shell command without escaping or validating special characters. This allows command separators such as semicolons, pipes, and backticks to be interpreted by the underlying shell, enabling command injection attacks.

Attack Vector

The attack can be performed remotely over the network. An attacker with valid administrative credentials sends a malicious HTTP POST request to the /goform/setSysAdm endpoint with a crafted passwd1 parameter containing shell metacharacters and arbitrary commands.

The vulnerability mechanism involves injecting shell commands through the password parameter. For example, an attacker could append command separators followed by malicious commands to the legitimate password value. When the router processes this input through the doSystem function, the injected commands execute with elevated privileges. Technical details and proof-of-concept information are available in the GitHub RCE Documentation.

Detection Methods for CVE-2026-2182

Indicators of Compromise

• Unusual HTTP POST requests to /goform/setSysAdm containing shell metacharacters (;, |, $(), backticks) in the passwd1 parameter
• Unexpected outbound network connections from the router to external IP addresses
• Unauthorized configuration changes or new user accounts on the router
• Presence of reverse shell connections or suspicious processes running on the device

Detection Strategies

• Implement network intrusion detection rules to identify HTTP requests containing command injection patterns targeting the /goform/setSysAdm endpoint
• Monitor router logs for repeated failed or successful authentication attempts followed by configuration change requests
• Deploy network traffic analysis to detect anomalous outbound connections originating from router management interfaces
• Utilize application-layer firewalls to inspect and block requests with malicious payloads to known vulnerable endpoints

Monitoring Recommendations

• Enable comprehensive logging on network perimeter devices to capture all traffic to and from router management interfaces
• Establish baseline behavior for administrative access patterns and alert on deviations
• Implement real-time monitoring of router CPU and memory usage that may indicate unauthorized process execution
• Review authentication logs regularly for signs of credential compromise or brute-force attempts

How to Mitigate CVE-2026-2182

Immediate Actions Required

• Restrict access to the router's administrative interface to trusted internal networks only using firewall rules or ACLs
• Change default administrative credentials immediately if still in use
• Implement multi-factor authentication for administrative access where supported
• Segment the router management network from general user traffic to limit exposure

Patch Information

At the time of this advisory, no vendor patch has been publicly released for this vulnerability. Organizations should monitor the VulDB advisory and UTT's official channels for security updates. The GitHub documentation provides additional technical details about this vulnerability.

Workarounds

• Disable remote administrative access and only allow local console management until a patch is available
• Implement a web application firewall (WAF) in front of the router's management interface to filter malicious input patterns
• Use network access control lists to restrict management interface access to specific authorized IP addresses only
• Consider replacing vulnerable devices with alternative router solutions that do not have this vulnerability

Network administrators should implement access restrictions at the network level to prevent exploitation. This includes configuring firewall rules to block external access to the management interface and limiting internal access to authorized administrator workstations only.