CVE-2026-38063 Overview
CVE-2026-38063 is a command injection vulnerability affecting Tenda 5G03 routers running firmware version V05.03.02.04 (Version 1.0). The flaw resides in the action_radio_on_with_ia_apn function, which fails to sanitize input passed through the ia parameter. An unauthenticated attacker can supply crafted input to inject shell metacharacters and execute arbitrary operating system commands on the device. The vulnerability is categorized under CWE-78 (Improper Neutralization of Special Elements used in an OS Command).
Critical Impact
Remote unauthenticated attackers can execute arbitrary OS commands on affected Tenda 5G03 routers, leading to full device compromise, traffic interception, and lateral network movement.
Affected Products
- Tenda 5G03 router
- Firmware version V05.03.02.04
- Version 1.0 release
Discovery Timeline
- 2026-06-15 - CVE-2026-38063 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2026-38063
Vulnerability Analysis
The vulnerability resides in the action_radio_on_with_ia_apn handler exposed by the Tenda 5G03 web management interface. This handler is responsible for enabling the radio with a specified Internet Access (IA) Access Point Name (APN) configuration. The function accepts the ia parameter directly from HTTP request data and incorporates it into a system command invocation without proper sanitization or argument escaping.
Because the affected handler is reachable over the network and requires no authentication or user interaction, attackers can issue a single crafted HTTP request to achieve remote code execution with the privileges of the web service, typically root on embedded SOHO routers. Successful exploitation grants the attacker the ability to modify router configuration, intercept LAN traffic, pivot into internal networks, and persist on the device.
Root Cause
The root cause is the unsafe concatenation of attacker-controlled input from the ia parameter into a shell command string. The firmware passes the parameter to a function such as system() or popen() without filtering shell metacharacters (;, |, &, backticks, $()). This is a textbook CWE-78 OS Command Injection condition common to consumer-grade embedded Linux devices.
Attack Vector
The attack vector is network-based and requires no privileges or user interaction. An attacker submits an HTTP request to the management interface of the router with shell metacharacters embedded in the ia parameter. The injected payload is concatenated into a shell command and executed by the router's command interpreter. Refer to the GitHub IoT Vulnerability Repository for proof-of-concept technical details.
Detection Methods for CVE-2026-38063
Indicators of Compromise
- HTTP requests to the router management interface containing the path or parameter action_radio_on_with_ia_apn with shell metacharacters such as ;, |, &&, or backticks in the ia parameter
- Unexpected outbound connections from the router to attacker-controlled infrastructure
- New or modified processes running on the router outside of normal firmware binaries
- Unauthorized changes to router DNS, routing, or firewall configuration
Detection Strategies
- Inspect web server logs on the router (where accessible) for POST or GET requests targeting action_radio_on_with_ia_apn with non-alphanumeric characters in the ia value
- Deploy network-based intrusion detection signatures that flag HTTP requests carrying shell metacharacters in router management parameters
- Monitor for anomalous DNS resolution and outbound traffic patterns originating from the router's WAN or LAN interfaces
Monitoring Recommendations
- Capture and analyze network flows to and from the router, alerting on connections to unfamiliar external hosts
- Track configuration drift on the router by periodically exporting and diffing its configuration
- Restrict and log all administrative access attempts to the router management interface
How to Mitigate CVE-2026-38063
Immediate Actions Required
- Disable remote (WAN-side) administration on the Tenda 5G03 router immediately
- Restrict access to the web management interface to a dedicated management VLAN or trusted host
- Replace default administrative credentials and audit existing accounts on the device
- Inspect the router for signs of compromise, including unexpected processes, modified DNS settings, and unauthorized firmware modifications
Patch Information
No vendor patch was referenced in the published advisory at the time of CVE assignment. Administrators should monitor Tenda's official support channels and the GitHub IoT Vulnerability Repository for firmware updates addressing the action_radio_on_with_ia_apn handler.
Workarounds
- Block external access to the router's HTTP/HTTPS management ports at the network perimeter
- Place the router behind an upstream firewall that filters HTTP requests containing shell metacharacters in management parameters
- Consider replacing the affected device with a supported model if a firmware fix is not made available by the vendor
# Example iptables rules to restrict management interface access
iptables -A INPUT -i wan0 -p tcp --dport 80 -j DROP
iptables -A INPUT -i wan0 -p tcp --dport 443 -j DROP
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.
