CVE-2025-50665: D-Link DI-8003 Buffer Overflow Vulnerability

CVE-2025-50665 Overview

A buffer overflow vulnerability exists in D-Link DI-8003 firmware version 16.07.26A1 due to improper handling of input parameters in the /web_keyword.asp endpoint. An attacker can exploit this vulnerability by sending a crafted HTTP GET request via the name, en, time, mem_gb2312, and mem_utf8 parameters. This firmware vulnerability in the D-Link router could allow attackers to corrupt memory and potentially execute arbitrary code on the affected device.

Critical Impact

This buffer overflow vulnerability could allow remote attackers to crash the device or potentially achieve code execution by sending maliciously crafted HTTP requests to the vulnerable web management interface.

Affected Products

• D-Link DI-8003 Firmware Version 16.07.26A1
• D-Link DI-8003 Router Series with vulnerable firmware

Discovery Timeline

• 2026-04-08 - CVE-2025-50665 published to NVD
• 2026-04-08 - Last updated in NVD database

Technical Details for CVE-2025-50665

Vulnerability Analysis

This vulnerability resides in the web management interface of the D-Link DI-8003 router, specifically within the /web_keyword.asp endpoint. The affected endpoint fails to properly validate the length of user-supplied input before copying it into fixed-size memory buffers. When processing HTTP GET requests, the application accepts multiple parameters including name, en, time, mem_gb2312, and mem_utf8 without implementing adequate bounds checking.

The lack of proper input validation allows an attacker to supply oversized data that exceeds the allocated buffer space, resulting in memory corruption. This type of firmware vulnerability is particularly concerning in IoT devices where security patches may be delayed or unavailable, and devices often remain connected to networks for extended periods.

Root Cause

The root cause of this vulnerability is improper input validation and insufficient bounds checking in the web application code handling the /web_keyword.asp endpoint. The firmware does not properly sanitize or limit the length of input parameters before copying them into stack or heap buffers, leading to classic buffer overflow conditions. This represents a common implementation flaw in embedded device firmware where memory-safe programming practices are not consistently applied.

Attack Vector

An attacker can exploit this vulnerability remotely by crafting a malicious HTTP GET request targeting the /web_keyword.asp endpoint. The attack requires network access to the device's web management interface. The exploitation involves sending specially crafted values in the vulnerable parameters (name, en, time, mem_gb2312, or mem_utf8) that exceed expected buffer sizes.

The vulnerable endpoint processes HTTP GET requests, meaning exploitation could potentially be performed through direct requests to the router's management interface. If the management interface is exposed to the internet or accessible from a compromised internal network, the attack surface increases significantly.

For technical details and proof-of-concept information, researchers can refer to the GitHub IoT Vulnerability Collection and the D-Link Security Bulletin.

Detection Methods for CVE-2025-50665

Indicators of Compromise

• Unusual HTTP GET requests to /web_keyword.asp with abnormally long parameter values
• Device crashes or unexpected reboots following web interface access
• Anomalous network traffic patterns originating from the affected D-Link router
• Web server error logs showing malformed requests to the vulnerable endpoint

Detection Strategies

• Monitor HTTP traffic to D-Link DI-8003 devices for requests containing oversized parameters in the name, en, time, mem_gb2312, or mem_utf8 fields
• Implement intrusion detection rules to flag HTTP GET requests to /web_keyword.asp with parameter lengths exceeding normal thresholds
• Deploy network monitoring to detect unusual outbound connections from router devices that may indicate successful exploitation
• Use firmware scanning tools to identify vulnerable D-Link DI-8003 devices running firmware version 16.07.26A1

Monitoring Recommendations

• Enable logging on the D-Link device's web management interface if available
• Implement network segmentation to isolate IoT devices and monitor traffic crossing segment boundaries
• Deploy SentinelOne Singularity for network-connected assets to detect anomalous behavior patterns
• Establish baseline behavior for router management interface access and alert on deviations

How to Mitigate CVE-2025-50665

Immediate Actions Required

• Restrict access to the D-Link DI-8003 web management interface to trusted IP addresses only
• Disable remote management if not required for operations
• Implement firewall rules to block external access to the router's administrative interface
• Monitor the D-Link Security Bulletin for firmware updates addressing this vulnerability

Patch Information

At the time of publication, consult the D-Link Security Bulletin for the latest patch availability and firmware updates for the DI-8003 router series. Organizations should apply security patches as soon as they become available from D-Link. Given the nature of buffer overflow vulnerabilities in firmware, updating to a patched version is the most effective remediation.

Workarounds

• Disable the web management interface entirely and use alternative management methods if available
• Place the D-Link DI-8003 behind a firewall that restricts access to the management interface
• Implement network access controls to limit which devices can communicate with the router's web interface
• Consider replacing end-of-life devices that may not receive security updates

# Example firewall rule to restrict access to router management interface
# Adjust interface and IP addresses for your environment
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP