CVE-2026-4467: Comfast CF-AC100 RCE Vulnerability

CVE-2026-4467 Overview

A command injection vulnerability has been identified in the Comfast CF-AC100 wireless access controller running firmware version 2.6.0.8. This vulnerability affects the /cgi-bin/mbox-config endpoint, specifically when the method=SET and section=wireless_device_dissoc parameters are used. Due to improper input validation, an attacker can inject arbitrary system commands through manipulated input, leading to potential remote code execution on the affected device.

Critical Impact

Remote attackers with administrative privileges can execute arbitrary commands on the device, potentially leading to complete system compromise, network lateral movement, or use of the device as a pivot point for further attacks.

Affected Products

• Comfast CF-AC100 Firmware Version 2.6.0.8

Discovery Timeline

• 2026-03-20 - CVE-2026-4467 published to NVD
• 2026-03-20 - Last updated in NVD database

Technical Details for CVE-2026-4467

Vulnerability Analysis

This vulnerability falls under CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component), commonly known as injection. The Comfast CF-AC100 wireless controller fails to properly sanitize user-supplied input before passing it to system commands. When an authenticated administrator sends a specially crafted request to the /cgi-bin/mbox-config endpoint with method=SET and section=wireless_device_dissoc, the device processes the input without adequate validation, allowing command metacharacters to be interpreted by the underlying shell.

The attack requires network access and administrative (high) privileges on the target device, but once those conditions are met, exploitation is straightforward with low attack complexity. The vulnerability can result in confidentiality, integrity, and availability impacts as the attacker gains the ability to execute arbitrary commands with the privileges of the web service process.

Root Cause

The root cause of this vulnerability is insufficient input validation and sanitization in the CGI handler for wireless device dissociation configuration. The application directly incorporates user-controlled input into system command execution without proper escaping or validation of special characters. This allows attackers to break out of the intended command context and execute additional arbitrary commands.

Attack Vector

The attack is executed remotely over the network. An attacker with valid administrative credentials can craft malicious HTTP requests targeting the vulnerable CGI endpoint. By injecting shell metacharacters (such as ;, |, &&, or backticks) into the request parameters, the attacker can append or chain additional commands that will be executed by the underlying operating system.

The vulnerability is documented in a GitHub CVE Analysis that provides additional technical details. The exploit methodology involves sending a crafted POST request to the /cgi-bin/mbox-config endpoint with malicious payload embedded in parameters that are passed unsanitized to shell commands. This can allow attackers to execute system commands, read sensitive files, establish reverse shells, or modify device configuration.

Detection Methods for CVE-2026-4467

Indicators of Compromise

• Unusual HTTP requests to /cgi-bin/mbox-config containing shell metacharacters such as ;, |, &&, $(, or backticks
• Unexpected processes spawned by the web server process on the CF-AC100 device
• Outbound network connections from the device to unknown external IP addresses
• Modified configuration files or unexpected system binaries on the device

Detection Strategies

• Monitor network traffic for HTTP requests to /cgi-bin/mbox-config with suspicious parameter values containing command injection patterns
• Implement Web Application Firewall (WAF) rules to detect and block requests containing shell metacharacters targeting CGI endpoints
• Enable logging on the CF-AC100 device and review logs for unusual administrative actions or command execution attempts

Monitoring Recommendations

• Configure network intrusion detection systems (IDS/IPS) to alert on requests containing injection patterns targeting the vulnerable endpoint
• Monitor authentication logs for the CF-AC100 web interface to detect unauthorized administrative access attempts
• Establish baseline network behavior for the device and alert on deviations such as unexpected outbound connections

How to Mitigate CVE-2026-4467

Immediate Actions Required

• Restrict network access to the CF-AC100 management interface to trusted administrative networks only
• Implement strong, unique administrative credentials and enable multi-factor authentication if supported
• Place the device behind a properly configured firewall that blocks direct internet access to the management interface
• Consider disabling remote management if not required and manage the device only via local connections

Patch Information

The vendor (Comfast) was contacted regarding this vulnerability but did not respond. As of the last NVD update on 2026-03-20, no official patch is available. Administrators should monitor the vendor's support channels for future firmware updates that address this vulnerability.

For additional technical details and tracking information, refer to:

• VulDB Entry #351757
• VulDB CTI ID #351757

Workarounds

• Implement network segmentation to isolate the CF-AC100 from critical network resources and limit lateral movement potential
• Deploy a reverse proxy or WAF in front of the device to filter malicious requests containing command injection patterns
• Disable the vulnerable CGI functionality if feasible and alternative management methods are available
• Consider replacing the device with an alternative product from a vendor that provides active security support

# Example: Firewall rule to restrict management access (adjust for your environment)
# Allow management access only from trusted admin network
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP