CVE-2025-50645: D-Link DI-8003 Buffer Overflow Vulnerability

CVE-2025-50645 Overview

A buffer overflow vulnerability has been discovered in the D-Link DI-8003 router firmware version 16.07.26A1. The vulnerability exists in the pppoe_list_opt.asp endpoint, where the s parameter fails to properly validate input length. By sending a crafted HTTP request with an excessively large value for the s parameter, an attacker can trigger a buffer overflow condition, potentially leading to denial of service or arbitrary code execution on affected devices.

Critical Impact

Successful exploitation of this buffer overflow vulnerability in D-Link DI-8003 routers could allow attackers to crash the device, execute arbitrary code, or gain unauthorized access to the network infrastructure.

Affected Products

• D-Link DI-8003 firmware version 16.07.26A1

Discovery Timeline

• April 8, 2026 - CVE CVE-2025-50645 published to NVD
• April 8, 2026 - Last updated in NVD database

Technical Details for CVE-2025-50645

Vulnerability Analysis

This vulnerability is classified as a buffer overflow, a common memory corruption issue found in embedded devices and IoT firmware. The D-Link DI-8003 router's web management interface contains a vulnerable endpoint at pppoe_list_opt.asp that processes the s parameter without adequate bounds checking.

When the router receives an HTTP request to this endpoint, it copies the value of the s parameter into a fixed-size buffer in memory. The implementation fails to verify that the input length does not exceed the allocated buffer size. This oversight allows an attacker to supply an oversized value that overwrites adjacent memory regions, corrupting critical data structures or control flow information on the stack.

Buffer overflows in network devices are particularly concerning because they can be exploited remotely without authentication, potentially allowing attackers to gain a foothold in the target network or disrupt network services.

Root Cause

The root cause of this vulnerability is improper input validation in the pppoe_list_opt.asp endpoint handler. The firmware does not implement proper boundary checks when copying user-supplied data from the s parameter into a fixed-size memory buffer. This lack of input length validation is a classic programming error that leads to buffer overflow conditions in C/C++ codebases commonly used in embedded systems.

Attack Vector

The attack can be executed remotely by sending a specially crafted HTTP request to the vulnerable endpoint on the D-Link DI-8003 router's web management interface. The attacker must have network access to the device's management interface, which may be exposed on the local network or, in misconfigured deployments, accessible from the internet.

The exploitation process involves:

1. Identifying a D-Link DI-8003 device running vulnerable firmware version 16.07.26A1
2. Crafting an HTTP request to the pppoe_list_opt.asp endpoint with an oversized s parameter
3. Sending the malicious request to trigger the buffer overflow condition
4. Potentially gaining code execution or causing a denial of service

For technical details and proof-of-concept information, refer to the GitHub IoT Vulnerability Collection.

Detection Methods for CVE-2025-50645

Indicators of Compromise

• Unusual HTTP requests to pppoe_list_opt.asp with abnormally large parameter values
• Router crashes or unexpected reboots without administrative action
• Anomalous network traffic patterns originating from or targeting the router's management interface
• Log entries showing malformed requests to the PPPoE configuration endpoints

Detection Strategies

• Monitor HTTP traffic to D-Link router management interfaces for requests containing oversized parameters
• Implement network intrusion detection rules to flag requests to pppoe_list_opt.asp with s parameter values exceeding normal operational lengths
• Deploy web application firewall rules to block requests with excessively long query parameters to IoT device management interfaces
• Use asset inventory tools to identify D-Link DI-8003 devices running vulnerable firmware versions

Monitoring Recommendations

• Enable and review router access logs for suspicious activity targeting the web management interface
• Implement network segmentation to isolate IoT devices and monitor traffic crossing segment boundaries
• Set up alerts for repeated failed or malformed requests to router management endpoints
• Monitor for unexpected device reboots or service disruptions that may indicate exploitation attempts

How to Mitigate CVE-2025-50645

Immediate Actions Required

• Restrict access to the D-Link DI-8003 management interface to trusted IP addresses only
• Disable remote management if not required for operational purposes
• Place the router behind a firewall that blocks external access to the management 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 official patch availability and updated firmware releases. Users should regularly check for security updates and apply patches as soon as they become available from the vendor.

Workarounds

• Implement access control lists (ACLs) to restrict management interface access to specific trusted IP addresses
• Disable the web management interface if command-line or other management methods are available
• Deploy network-level filtering to block requests with oversized parameters from reaching vulnerable endpoints
• Consider replacing end-of-life devices with currently supported models that receive regular security updates

If ACL restrictions are available on your network equipment, configure rules to limit access to the router's management interface:

# Example network ACL configuration (adjust for your environment)
# Restrict access to router management interface (typically port 80/443)
# Allow only trusted management subnet
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP