CVE-2026-5352 Overview
A command injection vulnerability has been identified in the Trendnet TEW-657BRM wireless router firmware version 1.00.1. This security flaw impacts the Edit function within the /setup.cgi file, where improper handling of the pcdb_list argument allows attackers to inject and execute arbitrary operating system commands. The vulnerability can be exploited remotely over the network by authenticated attackers.
Critical Impact
This OS command injection vulnerability enables remote attackers to execute arbitrary commands on affected Trendnet TEW-657BRM routers, potentially leading to complete device compromise, network infiltration, and persistent backdoor access.
Affected Products
- Trendnet TEW-657BRM Firmware Version 1.00.1
- Trendnet TEW-657BRM (End-of-Life since June 23, 2011)
Discovery Timeline
- April 2, 2026 - CVE-2026-5352 published to NVD
- April 2, 2026 - Last updated in NVD database
Technical Details for CVE-2026-5352
Vulnerability Analysis
This vulnerability is classified as CWE-77 (Improper Neutralization of Special Elements used in a Command - Command Injection). The affected device's web management interface fails to properly sanitize user-supplied input in the pcdb_list parameter before passing it to system shell commands.
The vulnerability exists in the Edit function of the /setup.cgi CGI script, which is responsible for handling configuration changes. When processing the pcdb_list argument, the firmware directly incorporates user input into OS command execution without adequate input validation or sanitization. This allows an authenticated attacker with network access to inject shell metacharacters and execute arbitrary commands with the privileges of the web server process, typically running as root on embedded devices.
Given that the Trendnet TEW-657BRM has been discontinued since June 2011 (over 14 years), no security patches are available. The vendor has confirmed they no longer provide support for this product and cannot verify the vulnerability. Organizations still operating this hardware should consider it inherently insecure.
Root Cause
The root cause of this vulnerability is improper input validation in the /setup.cgi script's Edit function. The pcdb_list parameter value is passed directly to system shell execution without sanitizing shell metacharacters such as semicolons, pipes, backticks, or command substitution sequences. This allows attackers to break out of the intended command context and execute arbitrary system commands on the underlying Linux-based operating system.
Attack Vector
The attack can be launched remotely over the network against the router's web management interface. An attacker with valid credentials (or in scenarios where default credentials are in use) can send a specially crafted HTTP request to /setup.cgi with malicious shell commands embedded in the pcdb_list parameter. The injected commands execute with the privileges of the web server, typically root on embedded devices, allowing full system compromise.
The exploitation requires network access to the device's management interface and low-privilege authentication. Given that many legacy routers retain default credentials or have weak authentication configurations, the practical exploitability of this vulnerability is significant.
Detection Methods for CVE-2026-5352
Indicators of Compromise
- Unusual HTTP requests to /setup.cgi containing shell metacharacters in the pcdb_list parameter
- Unexpected outbound connections from the router to external IP addresses
- Anomalous processes spawned on the router device
- Configuration changes or new user accounts created without administrator action
Detection Strategies
- Monitor web server logs for requests to /setup.cgi with suspicious characters (;, |, &, backticks, $()) in query parameters
- Implement network intrusion detection rules to identify command injection patterns in HTTP traffic destined for router management interfaces
- Deploy SentinelOne Singularity for network visibility and endpoint detection to identify lateral movement from compromised network devices
Monitoring Recommendations
- Enable logging on network devices and forward logs to a centralized SIEM for analysis
- Implement network segmentation to restrict access to router management interfaces
- Monitor for unusual traffic patterns originating from or directed at legacy network infrastructure
How to Mitigate CVE-2026-5352
Immediate Actions Required
- Identify and inventory all Trendnet TEW-657BRM devices in the network environment
- Immediately disconnect affected devices from production networks or isolate them in a restricted network segment
- Replace end-of-life Trendnet TEW-657BRM routers with modern, supported network equipment
- Review network logs for signs of prior exploitation
Patch Information
No security patch is available for this vulnerability. The Trendnet TEW-657BRM was discontinued and reached end-of-life on June 23, 2011. Trendnet has confirmed they no longer provide support for this product and will not be releasing security updates. The vendor has stated they will make an announcement on their website's product support page and notify customers who registered their products.
For additional technical details, see the GitHub Vulnerability Documentation and VulDB Vulnerability Details.
Workarounds
- Disable remote management access to the router's web interface
- Implement strict network access control lists (ACLs) to limit management interface access to trusted IP addresses only
- Place the device behind a firewall that can filter malicious HTTP requests
- Replace the end-of-life device with a currently supported router model as soon as possible
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
