Critical Vulnerability Alert: CVE-2025-22949 – Tenda AC9 Router Command Injection

🚨 Technical Analysis of CVE-2025–22949 — Tenda AC9 Router Command Injection .

📝 Overview of the Vulnerability

The vulnerability is a command injection flaw that exists in the HTTP request handler for the /goform/SetSambaCfg endpoint. This occurs due to insufficient input validation, where the application does not properly sanitize user-supplied inputs, allowing malicious data to be interpreted as system commands.

Attackers can craft specially constructed HTTP POST requests to exploit this flaw and execute arbitrary operating system commands on the router. Successful exploitation could lead to full system compromise of the router, giving attackers control over network traffic and connected devices.

🔎 Technical Details

1. Vulnerable Endpoint:

/goform/SetSambaCfg

This endpoint is responsible for handling Samba configuration changes. Parameters sent to this endpoint are processed by the router’s backend without adequate validation, leading to the vulnerability.

2. Vulnerability Type:

Command Injection

The flaw is triggered by injecting system commands into certain parameters sent in the HTTP POST request. Specifically, attackers exploit the lack of filtering on user input that gets passed directly to system commands executed by the router’s underlying Linux-based OS.

3. Sample Exploit Payload:

• In the payload above, the attacker inserts the malicious command (<malicious_command>) after the samba_user parameter.

• The router backend processes this unsanitized input, appending it to a system command, and executes it.

4. Potential Malicious Commands:

Attackers can execute commands such as:

• Network enumeration: ping or nslookup commands to probe internal devices.

• Data exfiltration: Redirect sensitive data to an external server via curl or wget.

• Persistence: Inject scripts to maintain long-term access to the router.

⚠️ Impact of Exploitation

1. Router Compromise:

Attackers can take full control of the router, giving them the ability to change configurations, disable security settings, or brick the device.

2. Network Traffic Monitoring:

Once compromised, attackers can monitor all incoming and outgoing network traffic, potentially exposing sensitive information such as usernames, passwords, or financial data.

3. Further Exploitation:

The attacker can pivot from the router to other devices on the network, enabling lateral movement to compromise PCs, IoT devices, or servers.

💡 Mitigation and Recommendations

1. Firmware Update

• Tenda has not yet confirmed a patch, but users should visit the Tenda Official Website to check for any firmware updates addressing this issue.

2. Restrict Access

• Disable remote management (WAN access) on the router.

• Limit access to the router’s admin interface by restricting it to trusted IP addresses.

3. Strong Credentials

• Change the router’s default admin credentials to a strong and unique password.

4. Network Segmentation

• Place IoT devices and critical systems on separate VLANs to limit the impact of a compromise.

5. Monitor for Suspicious Activity

• Use a network monitoring tool to identify unusual traffic patterns or unauthorized access attempts.

🌐 Why This Matters

Exploiting vulnerabilities like this can have far-reaching consequences, not only for individual users but for businesses relying on these devices for connectivity. Attackers gaining control of a router effectively compromise an entire network, leading to data breaches, ransomware attacks, or service disruptions.