CVE-2026-2686: SECCN Dingcheng G10 RCE Vulnerability

CVE-2026-2686 Overview

A critical OS command injection vulnerability has been identified in SECCN Dingcheng G10 version 3.1.0.181203. This security flaw impacts the qq function within the /cgi-bin/session_login.cgi file. Through manipulation of the User argument, an unauthenticated attacker can inject arbitrary operating system commands that execute on the target device. The attack can be carried out remotely over the network without requiring any user interaction or authentication credentials. The exploit has been publicly disclosed and may already be in active use.

Critical Impact

This vulnerability allows unauthenticated remote attackers to execute arbitrary OS commands on affected SECCN Dingcheng G10 devices, potentially leading to complete system compromise, data exfiltration, and lateral movement within the network.

Affected Products

• SECCN Dingcheng G10 version 3.1.0.181203

Discovery Timeline

• 2026-02-19 - CVE-2026-2686 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2026-2686

Vulnerability Analysis

This vulnerability is classified as CWE-77 (Improper Neutralization of Special Elements used in a Command), commonly known as OS command injection. The affected component is a CGI script responsible for handling session login functionality on the SECCN Dingcheng G10 network device.

The vulnerable code path exists within the qq function of /cgi-bin/session_login.cgi. When processing the User parameter, the application fails to properly sanitize user-supplied input before incorporating it into operating system commands. This allows attackers to append or inject malicious shell commands that are then executed with the privileges of the web server process.

Given the network-accessible nature of this endpoint and the absence of authentication requirements, this vulnerability presents a significant risk to organizations deploying affected devices. An attacker can leverage this flaw to establish persistent access, deploy malware, pivot to internal networks, or exfiltrate sensitive configuration data from the device.

Root Cause

The root cause of this vulnerability is insufficient input validation and sanitization in the session_login.cgi script. The User parameter is directly incorporated into a system command without proper escaping or validation of special characters. This allows command separators (such as ;, |, &&, or backticks) and additional command payloads to be injected and executed by the underlying operating system shell.

Attack Vector

The attack is network-based and can be executed remotely without authentication. An attacker sends a crafted HTTP request to the /cgi-bin/session_login.cgi endpoint with a malicious payload in the User parameter. The injected commands are then executed on the device with the privileges of the web server process, typically running as root or with elevated permissions on embedded devices.

The exploitation flow involves:

1. Identifying a vulnerable SECCN Dingcheng G10 device exposed to the network
2. Crafting an HTTP request to /cgi-bin/session_login.cgi with a malicious User parameter
3. Including shell metacharacters and arbitrary commands in the parameter value
4. The device executes the injected commands, returning output or establishing a reverse shell

Technical details and proof-of-concept information are available in the GitHub RCE Vulnerability Document.

Detection Methods for CVE-2026-2686

Indicators of Compromise

• Unusual HTTP requests to /cgi-bin/session_login.cgi containing shell metacharacters (;, |, &&, $(, backticks) in the User parameter
• Unexpected outbound connections from SECCN Dingcheng G10 devices to external IP addresses
• New or modified files in web-accessible directories or system directories on the device
• Unusual process spawning from the web server process (e.g., sh, bash, wget, curl, nc)

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing shell metacharacters in the User parameter of session_login.cgi
• Monitor HTTP access logs for requests to /cgi-bin/session_login.cgi with suspicious parameter values
• Deploy network intrusion detection signatures to identify command injection patterns targeting this specific endpoint
• Establish baseline behavior for SECCN devices and alert on anomalous network connections or process activity

Monitoring Recommendations

• Enable verbose logging on SECCN Dingcheng G10 devices if available and forward logs to a centralized SIEM
• Monitor for reverse shell indicators such as outbound connections on common shell ports (4444, 1337, etc.)
• Implement network segmentation to isolate IoT/embedded devices from critical infrastructure
• Conduct regular vulnerability scans to identify exposed instances of the affected firmware version

How to Mitigate CVE-2026-2686

Immediate Actions Required

• Identify all SECCN Dingcheng G10 devices running firmware version 3.1.0.181203 in your environment
• Restrict network access to the device management interface using firewall rules or network segmentation
• Block external access to /cgi-bin/session_login.cgi until a patch is available
• Monitor affected devices for signs of compromise and investigate any anomalous activity

Patch Information

No official vendor patch has been identified at this time. Organizations should contact SECCN directly to inquire about firmware updates that address this vulnerability. Additional technical information is available through VulDB #346488.

Workarounds

• Implement strict network access controls to limit which IP addresses can reach the device's web interface
• Place affected devices behind a VPN or jump host to prevent direct external access
• Deploy a reverse proxy or WAF with input validation rules to filter malicious requests before they reach the device
• Disable the web management interface if not required for operational purposes

# Example: Restrict access to SECCN device using iptables
# Allow only trusted management network (10.0.0.0/24) to access device web interface
iptables -A INPUT -p tcp --dport 80 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP