CVE-2025-50673: D-Link DI-8003 Buffer Overflow Vulnerability

CVE-2025-50673 Overview

A buffer overflow vulnerability exists in D-Link DI-8003 firmware version 16.07.26A1 due to improper handling of the http_lanport parameter in the /webgl.asp endpoint. This vulnerability allows attackers to potentially execute arbitrary code or cause denial of service conditions by sending specially crafted HTTP requests to the vulnerable web interface.

Critical Impact

Remote attackers can exploit improper input validation in the router's web management interface to trigger a buffer overflow, potentially leading to device compromise or service disruption.

Affected Products

• D-Link DI-8003 firmware version 16.07.26A1

Discovery Timeline

• 2026-04-08 - CVE-2025-50673 published to NVD
• 2026-04-08 - Last updated in NVD database

Technical Details for CVE-2025-50673

Vulnerability Analysis

This buffer overflow vulnerability affects the web management interface of D-Link DI-8003 routers running firmware version 16.07.26A1. The vulnerability is triggered when the device processes user-supplied input through the http_lanport parameter at the /webgl.asp endpoint.

The core issue stems from insufficient bounds checking when handling the http_lanport parameter value. When an oversized or malformed value is submitted to this endpoint, the application fails to properly validate the input length before copying it into a fixed-size buffer, resulting in a classic buffer overflow condition.

As a firmware vulnerability in networking equipment, successful exploitation could allow an attacker to gain control over the router, intercept network traffic, or use the compromised device as a pivot point for further attacks on the internal network.

Root Cause

The root cause is improper input validation and lack of boundary checks when processing the http_lanport parameter in the /webgl.asp web endpoint. The firmware does not verify that user-supplied input fits within the allocated buffer space before performing memory copy operations, allowing attackers to overwrite adjacent memory regions.

Attack Vector

An attacker can exploit this vulnerability by sending a crafted HTTP request to the /webgl.asp endpoint containing an oversized value in the http_lanport parameter. The attack requires network access to the router's web management interface.

The exploitation typically involves:

1. Identifying a D-Link DI-8003 device running the vulnerable firmware version 16.07.26A1
2. Crafting an HTTP request to /webgl.asp with a malicious payload in the http_lanport parameter
3. Sending the request to overflow the buffer and potentially execute arbitrary code or crash the device

For technical details on this vulnerability, refer to the GitHub IoT Vulnerability Collection and the D-Link Security Bulletin.

Detection Methods for CVE-2025-50673

Indicators of Compromise

• Unexpected reboots or instability of D-Link DI-8003 routers
• Anomalous HTTP traffic targeting /webgl.asp endpoint with oversized parameter values
• Unauthorized configuration changes on affected devices
• Unusual outbound network connections originating from the router

Detection Strategies

• Monitor HTTP requests to D-Link router web interfaces for abnormally long http_lanport parameter values
• Implement network intrusion detection rules to identify buffer overflow exploitation attempts targeting /webgl.asp
• Deploy SentinelOne Singularity to detect and respond to exploit attempts targeting network infrastructure devices

Monitoring Recommendations

• Enable logging on network infrastructure to capture web management interface access attempts
• Implement network segmentation to isolate IoT and network devices from critical systems
• Regularly audit firmware versions across all D-Link devices in the environment

How to Mitigate CVE-2025-50673

Immediate Actions Required

• Check the D-Link Security Bulletin for available firmware updates addressing this vulnerability
• Restrict access to the router's web management interface to trusted networks only
• Disable remote management if not required for operations
• Place affected devices behind a firewall with strict access controls

Patch Information

Consult the D-Link Security Bulletin for the latest firmware updates and security advisories addressing CVE-2025-50673. Ensure you are running the most recent firmware version that addresses this buffer overflow vulnerability.

Workarounds

• Disable the web management interface entirely if administrative access is not required
• Implement network-level access controls to restrict who can reach the /webgl.asp endpoint
• Use a VPN or jump host to access the router management interface rather than exposing it directly
• Consider replacing end-of-life devices that may not receive security updates

# Example: Restrict management interface access via firewall rules
# Block external access to router management port
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