CVE-2026-2082: D-Link DIR-823X RCE Vulnerability

CVE-2026-2082 Overview

A command injection vulnerability has been identified in the D-Link DIR-823X router firmware version 250416. The vulnerability exists in the /goform/set_mac_clone endpoint, where improper handling of the mac argument allows remote attackers to inject and execute arbitrary operating system commands. This firmware vulnerability affects the router's web management interface and can be exploited remotely by authenticated attackers with administrative privileges.

Critical Impact

Successful exploitation of this OS command injection vulnerability could allow attackers to execute arbitrary commands on the affected D-Link router, potentially leading to complete device compromise, network traffic interception, or use of the device as a pivot point for further attacks.

Affected Products

• D-Link DIR-823X Firmware version 250416
• D-Link DIR-823X Hardware

Discovery Timeline

• 2026-02-07 - CVE-2026-2082 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2026-2082

Vulnerability Analysis

This vulnerability is classified as CWE-77 (Improper Neutralization of Special Elements used in a Command), commonly known as Command Injection. The affected endpoint /goform/set_mac_clone fails to properly sanitize user-supplied input in the mac parameter before incorporating it into system commands. When an authenticated administrator submits a specially crafted MAC address value containing shell metacharacters or command sequences, the router's firmware processes this input without adequate validation, allowing the injected commands to be executed with the privileges of the underlying system process.

The network-accessible nature of this vulnerability means that any attacker who has obtained administrative credentials to the router's web interface can remotely execute commands on the device. The exploit details have been publicly documented, increasing the risk of widespread exploitation.

Root Cause

The root cause of this vulnerability lies in insufficient input validation and sanitization within the MAC address cloning functionality. The /goform/set_mac_clone handler directly passes user-controlled input to shell commands without properly escaping special characters or implementing a whitelist-based validation approach. This allows shell metacharacters such as semicolons, pipes, backticks, or command substitution syntax to break out of the intended command context and execute attacker-controlled commands.

Attack Vector

The attack requires network access to the router's administrative interface and valid administrator credentials. An attacker can exploit this vulnerability by:

1. Authenticating to the D-Link DIR-823X web management interface with administrator privileges
2. Navigating to or directly accessing the /goform/set_mac_clone endpoint
3. Submitting a malicious payload in the mac parameter containing OS commands embedded within shell metacharacters
4. The injected commands execute on the router with the privileges of the web server process

The vulnerability affects confidentiality, integrity, and availability of the device, as arbitrary command execution can be used to extract sensitive data, modify system configurations, or disrupt router operations.

For detailed technical analysis and proof-of-concept information, refer to the GitHub Issue Discussion and VulDB Entry #344649.

Detection Methods for CVE-2026-2082

Indicators of Compromise

• Unexpected HTTP POST requests to /goform/set_mac_clone containing unusual characters or shell metacharacters in the mac parameter
• Anomalous processes spawning from the router's web server process
• Unusual outbound network connections from the router to external hosts
• Modified system files or configurations on the router without authorized changes

Detection Strategies

• Monitor web server logs for requests to /goform/set_mac_clone with payloads containing shell metacharacters such as ;, |, $(), or backticks
• Implement network intrusion detection rules to identify command injection patterns in HTTP traffic destined for D-Link router management interfaces
• Deploy endpoint detection capabilities that can identify anomalous command execution patterns on embedded devices where supported

Monitoring Recommendations

• Enable comprehensive logging on the D-Link DIR-823X management interface if supported by the firmware
• Monitor network traffic for unusual HTTP POST requests targeting router management endpoints
• Implement network segmentation to limit exposure of router management interfaces to trusted networks only
• Consider deploying a Web Application Firewall (WAF) in front of network management interfaces to filter malicious inputs

How to Mitigate CVE-2026-2082

Immediate Actions Required

• Restrict access to the router's administrative interface to trusted IP addresses only using firewall rules
• Disable remote management features if not required for operations
• Change default administrator credentials and implement strong passwords
• Isolate affected devices on a separate network segment until patches are available
• Monitor for any signs of compromise on affected devices

Patch Information

As of the last NVD update on 2026-02-10, no official patch information has been published by D-Link. Organizations should monitor the D-Link Official Website for firmware updates addressing this vulnerability. Check the VulDB Entry for updated remediation information.

Workarounds

• Disable the MAC cloning feature if not required for network operations
• Implement strict network access controls to limit which hosts can reach the router's management interface
• Use a VPN or jump host to access router management interfaces rather than exposing them directly
• Consider replacing affected devices with alternative hardware if patches are not forthcoming

# Network access restriction example (upstream firewall)
# Block external access to router management interface
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 80 -j DROP
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 443 -j DROP

# Allow management access only from trusted admin subnet
iptables -I FORWARD -s <ADMIN_SUBNET> -d <ROUTER_IP> -p tcp --dport 80 -j ACCEPT
iptables -I FORWARD -s <ADMIN_SUBNET> -d <ROUTER_IP> -p tcp --dport 443 -j ACCEPT