CVE-2026-5153 Overview
A command injection vulnerability has been discovered in Tenda CH22 firmware version 1.0.0.1. The vulnerability exists in the FormWriteFacMac function within the /goform/WriteFacMac endpoint. By manipulating the mac argument, an attacker can inject and execute arbitrary commands on the affected device. This vulnerability can be exploited remotely, and exploit code has been published and may be actively used.
Critical Impact
Remote attackers can exploit this command injection vulnerability to execute arbitrary commands on Tenda CH22 devices, potentially leading to complete device compromise, network infiltration, and unauthorized access to connected systems.
Affected Products
- Tenda CH22 Firmware version 1.0.0.1
- Tenda CH22 Hardware
Discovery Timeline
- 2026-03-30 - CVE-2026-5153 published to NVD
- 2026-04-02 - Last updated in NVD database
Technical Details for CVE-2026-5153
Vulnerability Analysis
This vulnerability is classified as a command injection flaw (CWE-77) with characteristics of injection attacks (CWE-74). The vulnerable component is the FormWriteFacMac function, which processes user-supplied input through the mac parameter without proper sanitization or validation. When a crafted request is sent to the /goform/WriteFacMac endpoint, the unsanitized mac argument is passed directly to system command execution functions, allowing attackers to inject arbitrary shell commands.
The attack vector is network-based, meaning an attacker with network access to the device's web management interface can exploit this vulnerability without physical access to the device. The vulnerability requires low privileges to exploit and does not require user interaction, making it particularly dangerous for devices exposed on networks.
Root Cause
The root cause of this vulnerability is improper input validation and sanitization in the FormWriteFacMac function. The mac parameter is not properly sanitized before being used in a system command context, allowing shell metacharacters and command separators to be interpreted as part of the executed command. This is a classic command injection pattern where user input is concatenated into shell commands without escaping or validation.
Attack Vector
An attacker can exploit this vulnerability by sending a specially crafted HTTP request to the /goform/WriteFacMac endpoint on the target Tenda CH22 device. The malicious request would include shell command injection payloads within the mac parameter. Common injection techniques include using command separators such as semicolons (;), pipes (|), or command substitution sequences to append malicious commands to the legitimate MAC address processing operation.
The vulnerability mechanism involves improper handling of user input in the FormWriteFacMac function. When a request is made to /goform/WriteFacMac, the mac parameter value is processed without adequate sanitization, allowing shell metacharacters to be interpreted. For detailed technical analysis and proof-of-concept information, refer to the GitHub Vulnerability Documentation.
Detection Methods for CVE-2026-5153
Indicators of Compromise
- Unusual HTTP POST requests to /goform/WriteFacMac containing shell metacharacters or command sequences in the mac parameter
- Unexpected process spawning or command execution originating from the web server process on Tenda CH22 devices
- Network traffic anomalies indicating command and control communication from router devices
- Modified system files or configurations on the Tenda CH22 device
Detection Strategies
- Implement network intrusion detection rules to identify suspicious requests to /goform/WriteFacMac endpoints containing injection patterns
- Monitor web server logs on Tenda CH22 devices for requests with unusual characters in the mac parameter such as semicolons, pipes, backticks, or dollar signs
- Deploy endpoint detection on network segments to identify anomalous behavior from IoT and network devices
Monitoring Recommendations
- Enable logging on all Tenda CH22 devices and forward logs to a centralized SIEM for analysis
- Implement network segmentation to isolate IoT and network infrastructure devices from critical systems
- Regularly audit network traffic patterns from router and access point devices for signs of compromise
How to Mitigate CVE-2026-5153
Immediate Actions Required
- Restrict network access to the Tenda CH22 web management interface to trusted IP addresses only
- Place affected devices behind a firewall and disable remote management if not required
- Monitor for and apply any firmware updates from Tenda addressing this vulnerability
- Consider replacing affected devices if no patch is available
Patch Information
At the time of publication, no official patch has been released by Tenda for this vulnerability. Organizations should monitor the Tenda Official Website for security advisories and firmware updates. Additional vulnerability details can be found at VulDB Vulnerability #354185.
Workarounds
- Disable remote management access to the Tenda CH22 device if it is not required for operations
- Implement network-level access controls to restrict which hosts can reach the /goform/ endpoints on affected devices
- Deploy a web application firewall (WAF) in front of the device management interface to filter malicious requests containing command injection patterns
- Isolate affected devices on a separate network segment with strict egress filtering
# Example firewall rule to restrict access to device management interface
# Allow only trusted management subnet to access web interface
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
