CVE-2026-2151: D-Link DIR-615 Firmware RCE Vulnerability

CVE-2026-2151 Overview

A critical OS command injection vulnerability has been discovered in D-Link DIR-615 wireless routers running firmware version 4.10. The vulnerability exists in the adv_firewall.php file, specifically within the DMZ Host Feature component. Attackers can exploit this flaw by manipulating the dmz_ipaddr parameter, allowing them to execute arbitrary operating system commands on the affected device. This vulnerability is remotely exploitable and affects an end-of-life product that is no longer supported by D-Link.

Critical Impact

Remote attackers with administrative access can achieve complete system compromise through OS command injection, potentially gaining full control over the router and enabling lateral movement within the network.

Affected Products

• D-Link DIR-615 Firmware version 4.10
• D-Link DIR-615 Hardware (all revisions running affected firmware)
• End-of-life products no longer receiving security updates from D-Link

Discovery Timeline

• 2026-02-08 - CVE CVE-2026-2151 published to NVD
• 2026-02-11 - Last updated in NVD database

Technical Details for CVE-2026-2151

Vulnerability Analysis

This vulnerability (CWE-77: Improper Neutralization of Special Elements used in a Command, CWE-78: Improper Neutralization of Special Elements used in an OS Command) affects the DMZ Host configuration functionality within the D-Link DIR-615 router's web management interface. The affected code resides in adv_firewall.php, which processes user-supplied input for the dmz_ipaddr parameter without proper sanitization or validation.

When an authenticated administrator configures the DMZ host feature, the supplied IP address value is directly incorporated into system commands executed by the router's underlying operating system. Due to insufficient input validation, an attacker can inject arbitrary shell commands by appending command separators and malicious payloads to the expected IP address input.

The attack requires network access and administrative privileges on the device. Once exploited, attackers can execute commands with the privileges of the web server process, typically root-level access on embedded devices, leading to complete device compromise.

Root Cause

The root cause of this vulnerability is improper input validation and sanitization in the adv_firewall.php file. The dmz_ipaddr parameter accepts user-controlled input that is passed directly to system shell commands without adequate filtering of special characters or command separators. This classic command injection pattern allows metacharacters such as semicolons, pipes, and backticks to break out of the intended command context and execute attacker-supplied commands.

Attack Vector

The attack vector is network-based and requires authenticated administrative access to the router's web interface. An attacker with valid administrative credentials can navigate to the DMZ configuration page and submit a malicious payload through the dmz_ipaddr field. The injected commands execute immediately on the underlying Linux-based operating system with elevated privileges.

Potential attack scenarios include:

The vulnerability in the DMZ Host Feature allows command injection through the dmz_ipaddr parameter. An attacker can craft a malicious request to the adv_firewall.php endpoint, injecting shell commands by manipulating the expected IP address format. For example, instead of providing a valid IP address, an attacker could append shell metacharacters followed by arbitrary commands, which would then be executed by the system. Technical details and proof-of-concept information are available in the Notion OS Command Injection writeup.

Detection Methods for CVE-2026-2151

Indicators of Compromise

• Unusual HTTP POST requests to /adv_firewall.php containing shell metacharacters (;, |, &, backticks, $()) in the dmz_ipaddr parameter
• Unexpected outbound network connections from the router to external IP addresses
• Anomalous processes running on the device not associated with normal router operations
• Modifications to router configuration files or firmware outside of normal administrative activity

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block command injection patterns in requests to the router's management interface
• Monitor network traffic for suspicious HTTP requests targeting /adv_firewall.php with malformed or oversized dmz_ipaddr values
• Deploy network-based intrusion detection systems (IDS) with signatures for command injection attempts against D-Link devices
• Review router access logs for authentication attempts and configuration changes from unexpected IP addresses

Monitoring Recommendations

• Enable and regularly review router access logs for suspicious administrative activity
• Monitor DNS queries from the router for connections to known malicious domains or unusual external hosts
• Implement network segmentation to isolate IoT and network devices from critical infrastructure
• Use SentinelOne Singularity to monitor for lateral movement attempts originating from compromised network devices

How to Mitigate CVE-2026-2151

Immediate Actions Required

• Restrict administrative access to the router's web interface to trusted IP addresses only using access control lists
• Disable remote administration if not required and limit management access to local network connections
• Change default administrative credentials and implement strong, unique passwords
• Consider replacing the affected end-of-life device with a currently supported router model

Patch Information

This vulnerability affects the D-Link DIR-615 router, which is an end-of-life product that is no longer supported by the manufacturer. D-Link has discontinued security updates for this device, and no official patch is available or expected. Organizations using affected devices should plan for immediate replacement with currently supported hardware that receives regular security updates.

For additional information, refer to D-Link Security Resources and the vulnerability database entries at VulDB ID #344853.

Workarounds

• Implement firewall rules at the network perimeter to block external access to the router's management interface (typically ports 80, 443, and 8080)
• Place the affected router behind a more secure network device that can filter malicious requests
• Disable the DMZ Host Feature if not required for network operations
• Deploy network monitoring to detect and alert on exploitation attempts while planning device replacement

# Example iptables rules to restrict management access
# Apply these on an upstream firewall or gateway device

# Block external access to router management ports
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP

# Allow management only from specific trusted admin workstation
iptables -I FORWARD -s 192.168.1.100 -d 192.168.1.1 -p tcp --dport 80 -j ACCEPT