CVE-2026-7469 Overview
A command injection vulnerability has been identified in the Tenda 4G300 router running firmware version US_4G300V1.0Mt_V1.01.42_CN_TDC01. This vulnerability affects the function sub_425A28 within the file /goform/DelFil, where improper handling of the delflag argument allows attackers to inject arbitrary system commands. The attack can be executed remotely over the network, and a proof-of-concept exploit has been publicly disclosed.
Critical Impact
Remote attackers with low privileges can execute arbitrary commands on the affected Tenda 4G300 router by exploiting insufficient input validation in the file deletion functionality.
Affected Products
- Tenda 4G300 Firmware US_4G300V1.0Mt_V1.01.42_CN_TDC01
Discovery Timeline
- 2026-04-30 - CVE CVE-2026-7469 published to NVD
- 2026-04-30 - Last updated in NVD database
Technical Details for CVE-2026-7469
Vulnerability Analysis
This vulnerability stems from improper neutralization of special elements used in a command (CWE-74 - Injection). The affected function sub_425A28 in the /goform/DelFil endpoint fails to properly sanitize user-supplied input through the delflag parameter before incorporating it into system commands. This allows an authenticated attacker to inject malicious shell commands that will be executed with the privileges of the web server process on the router.
The network-based attack vector makes this vulnerability exploitable remotely, though it requires authentication (low privileges). The exploit has been publicly documented, increasing the risk of widespread exploitation against exposed devices.
Root Cause
The root cause lies in inadequate input validation within the sub_425A28 function. The delflag argument is passed directly to command execution routines without proper sanitization or escaping of shell metacharacters. This represents a classic command injection flaw where user-controlled data is concatenated into system shell commands without appropriate neutralization of special characters such as semicolons, pipes, backticks, or command substitution syntax.
Attack Vector
The attack can be launched remotely over the network against the router's web administration interface. An attacker with valid credentials (even low-privileged) can craft a malicious HTTP request to the /goform/DelFil endpoint, manipulating the delflag parameter to include shell command injection payloads. These injected commands would then be executed on the underlying router operating system, potentially allowing the attacker to gain complete control of the device, intercept network traffic, pivot to internal networks, or disable security functions.
The vulnerability mechanism involves passing user input from the delflag parameter directly to system command execution without proper sanitization. An attacker can append shell metacharacters and arbitrary commands to the parameter value, which are then interpreted and executed by the underlying shell. For detailed technical analysis and proof-of-concept information, see the GitHub CVE PoC Documentation.
Detection Methods for CVE-2026-7469
Indicators of Compromise
- Unusual HTTP POST requests to /goform/DelFil containing shell metacharacters (;, |, $(, `) in the delflag parameter
- Unexpected processes spawned by the web server process on the router
- Outbound connections from the router to unknown external hosts
- Modified configuration files or new user accounts on the device
Detection Strategies
- Monitor web server logs for requests to /goform/DelFil with suspicious parameter values containing command injection patterns
- Implement network-level inspection to detect anomalous payloads in HTTP traffic destined for router management interfaces
- Deploy intrusion detection rules targeting common command injection syntax in the delflag parameter
Monitoring Recommendations
- Enable and regularly review access logs on the Tenda 4G300 management interface
- Set up alerts for authentication attempts from unexpected IP addresses
- Monitor for unusual outbound network connections originating from the router
How to Mitigate CVE-2026-7469
Immediate Actions Required
- Restrict access to the router's web management interface to trusted IP addresses only
- Disable remote management if not required
- Place the router behind a firewall that blocks external access to the management port
- Review router logs for any signs of exploitation attempts
Patch Information
At the time of publication, no vendor patch has been confirmed. Organizations should monitor the Tenda Official Website for firmware updates addressing this vulnerability. Additional vulnerability details are available at VulDB Vulnerability #360205.
Workarounds
- Implement network segmentation to isolate the router's management interface from untrusted networks
- Use strong, unique credentials for router authentication
- Consider replacing vulnerable devices with alternatives that receive regular security updates if no patch becomes available
- Deploy a web application firewall (WAF) or reverse proxy to filter malicious requests to the management interface
# Example iptables rule to restrict management access to trusted IP only
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.100 -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.
