CVE-2026-38061 Overview
CVE-2026-38061 is a command injection vulnerability affecting the Tenda 5G03 router running firmware version V05.03.02.04 (Version 1.0). The flaw resides in the action_set_volume function, where the volume parameter is passed to a system shell without proper sanitization. An unauthenticated attacker with network access to the device can inject arbitrary operating system commands. Successful exploitation grants the attacker code execution in the context of the router's web management process, typically running as root on embedded Linux devices. The weakness is classified under CWE-78: Improper Neutralization of Special Elements used in an OS Command.
Critical Impact
Unauthenticated remote attackers can execute arbitrary OS commands on affected Tenda 5G03 routers, leading to full device compromise.
Affected Products
- Tenda 5G03 router firmware V05.03.02.04
- Tenda 5G03 Version 1.0 hardware revision
- Deployments exposing the device web management interface to untrusted networks
Discovery Timeline
- 2026-06-15 - CVE-2026-38061 published to the National Vulnerability Database
- 2026-06-17 - Last updated in the NVD database
Technical Details for CVE-2026-38061
Vulnerability Analysis
The vulnerability exists in the action_set_volume handler exposed by the Tenda 5G03 web management interface. The handler reads the volume parameter from an HTTP request and concatenates the value into a shell command string. Because the parameter content is not validated or escaped, shell metacharacters such as ;, |, &, and backticks pass through and are interpreted by the underlying shell.
An attacker who can reach the router's HTTP service can submit a crafted request that appends arbitrary commands to the intended invocation. The injected commands execute with the privileges of the web service, which on Tenda consumer routers is generally root. Outcomes include credential harvesting from /etc, persistent backdoor installation, modification of DNS or routing tables to enable traffic interception, and recruitment of the device into a botnet.
The attack surface is amplified when administrators expose the management interface to the WAN, but lateral attackers on the LAN can exploit the same code path without authentication.
Root Cause
The root cause is missing input neutralization on the volume HTTP parameter before it is incorporated into an OS command, an instance of [CWE-78]. The function relies on direct string interpolation into a shell context rather than using parameterized execution or a strict allow-list of numeric values.
Attack Vector
Exploitation requires only network reachability to the device's HTTP management service. No authentication, user interaction, or prior foothold is needed. The attacker issues an HTTP request to the action_set_volume endpoint with a volume value containing shell metacharacters and the desired payload. Technical proof-of-concept artifacts are available in the GitHub PoC Repository.
Detection Methods for CVE-2026-38061
Indicators of Compromise
- HTTP requests to the router's management interface containing shell metacharacters (;, |, &, `, $()) in the volume parameter
- Unexpected outbound connections from the router to attacker-controlled hosts following HTTP traffic to action_set_volume
- New or modified files in router-writable paths such as /tmp, /var, or persistent NVRAM entries
- Unauthorized changes to DNS server settings, firewall rules, or administrative credentials
Detection Strategies
- Inspect HTTP request logs at network choke points for POST or GET requests targeting action_set_volume with non-numeric volume values
- Deploy IDS/IPS signatures that flag command injection patterns in HTTP parameters destined for management interfaces of embedded devices
- Baseline router behavior and alert on anomalous process execution or outbound connections originating from the device
Monitoring Recommendations
- Forward network flow data and HTTP metadata involving router management ports to a centralized analytics platform for correlation
- Monitor DNS query patterns from clients behind the router for sudden changes that indicate DNS hijacking
- Track firmware version inventory to identify devices running V05.03.02.04 of the Tenda 5G03
How to Mitigate CVE-2026-38061
Immediate Actions Required
- Restrict access to the router's HTTP management interface to trusted management VLANs only; block WAN-side administrative access
- Change default and weak administrative credentials, and disable remote management features that are not strictly required
- Segment IoT and consumer-grade routers from sensitive corporate networks to limit blast radius if the device is compromised
Patch Information
No vendor advisory or firmware update referencing CVE-2026-38061 is listed in the NVD entry at the time of publication. Administrators should monitor Tenda's official support channels for a firmware release that addresses the action_set_volume command injection and apply it as soon as it becomes available.
Workarounds
- Disable the router's web management interface on untrusted interfaces until a patched firmware is released
- Place the device behind an upstream firewall that filters HTTP requests to the management endpoint and drops payloads containing shell metacharacters
- Replace end-of-life or unpatched Tenda 5G03 units with vendor-supported equipment in environments where exposure cannot be mitigated
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
