CVE-2025-50667: D-Link DI-8003 Buffer Overflow Vulnerability

CVE-2025-50667 Overview

A buffer overflow vulnerability exists in D-Link DI-8003 firmware version 16.07.26A1 due to improper handling of the iface parameter in the /wan_line_detection.asp endpoint. This firmware vulnerability affects network router infrastructure and could potentially allow attackers to compromise the affected device through malicious input.

Critical Impact

Buffer overflow in network router firmware could lead to device compromise, network traffic interception, or denial of service conditions affecting network connectivity.

Affected Products

• D-Link DI-8003 with firmware version 16.07.26A1
• Network infrastructure devices running vulnerable firmware

Discovery Timeline

• 2026-04-08 - CVE CVE-2025-50667 published to NVD
• 2026-04-08 - Last updated in NVD database

Technical Details for CVE-2025-50667

Vulnerability Analysis

This buffer overflow vulnerability stems from insufficient bounds checking when processing the iface parameter submitted to the /wan_line_detection.asp endpoint on the D-Link DI-8003 router. When a user or attacker supplies an overly long or specially crafted value for the iface parameter, the application fails to properly validate the input length before copying it into a fixed-size memory buffer.

Buffer overflow vulnerabilities in embedded network devices like routers are particularly concerning because these devices often lack modern memory protection mechanisms such as ASLR (Address Space Layout Randomization) or stack canaries. Additionally, firmware in consumer-grade networking equipment may run with elevated privileges, meaning successful exploitation could grant full control over the device.

Root Cause

The root cause of this vulnerability is improper input validation in the firmware's handling of the iface parameter within the /wan_line_detection.asp web interface component. The affected code does not adequately verify that user-supplied input conforms to expected size constraints before processing, allowing an attacker to overflow the designated buffer.

Attack Vector

An attacker could exploit this vulnerability by sending a maliciously crafted HTTP request to the vulnerable endpoint on an exposed D-Link DI-8003 device. The attack would involve submitting an oversized or specially formatted iface parameter value to the /wan_line_detection.asp endpoint.

The vulnerability exists in the device's web management interface. If the management interface is accessible from untrusted networks (including the internet via misconfiguration or from the local network), attackers within reach could attempt exploitation. Successful exploitation could result in arbitrary code execution, denial of service, or device compromise.

For technical details regarding the vulnerability mechanism, refer to the GitHub IoT Vulnerability Collection which documents this and related IoT security issues.

Detection Methods for CVE-2025-50667

Indicators of Compromise

• Unexpected device reboots or crashes of D-Link DI-8003 routers
• Unusual HTTP requests to /wan_line_detection.asp with abnormally long iface parameter values
• Anomalous outbound network traffic from the router indicating potential compromise
• Unauthorized configuration changes or new administrative accounts on the device

Detection Strategies

• Monitor HTTP access logs for requests to /wan_line_detection.asp containing excessively long parameter values
• Implement network intrusion detection rules to identify buffer overflow exploitation patterns targeting D-Link devices
• Deploy web application firewall rules to filter requests with oversized parameters to the vulnerable endpoint
• Use firmware integrity verification tools to detect unauthorized modifications

Monitoring Recommendations

• Enable logging on D-Link router administrative interfaces and forward logs to a central SIEM
• Monitor for crash dumps or unexpected service restarts on affected devices
• Track firmware versions across network infrastructure to identify vulnerable deployments
• Implement network segmentation to limit exposure of router management interfaces

How to Mitigate CVE-2025-50667

Immediate Actions Required

• Restrict access to the router's web management interface to trusted networks only
• Disable remote management features if not required
• Implement firewall rules to block external access to the /wan_line_detection.asp endpoint
• Check the D-Link Security Bulletin for updated firmware releases

Patch Information

Organizations should monitor D-Link's official security resources for firmware updates addressing this vulnerability. Consult the D-Link Security Bulletin for the latest patch information and updated firmware versions.

Given that the D-Link DI-8003 is an older model, administrators should verify whether the device is still within the vendor's support lifecycle. If the device has reached end-of-life status, consider replacing it with a currently supported model that receives regular security updates.

Workarounds

• Disable the web management interface entirely if remote administration is not needed
• Place the router's management interface on an isolated VLAN accessible only to authorized administrators
• Implement network-level access controls (ACLs) to restrict which IP addresses can reach the management interface
• Use a VPN for administrative access rather than exposing the management interface directly

# Example: Restrict management access via firewall rules
# Block external access to router management interface
iptables -A INPUT -p tcp --dport 80 -s ! 192.168.1.0/24 -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 192.168.1.0/24 -j DROP

# Allow only specific admin workstation
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.100 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.100 -j ACCEPT