CVE-2025-50657: D-Link DI-8003 Buffer Overflow Vulnerability

CVE-2025-50657 Overview

CVE-2025-50657 is a stack-based buffer overflow vulnerability [CWE-121] affecting D-Link DI-8003 routers running firmware version 16.07.26A1. The flaw resides in the /trace.asp endpoint of the device's web management interface. Improper handling of the pid parameter allows a remote, unauthenticated attacker to send a crafted HTTP request that overruns a fixed-size stack buffer. Successful exploitation crashes the router and disrupts network connectivity for all downstream users. The vulnerability is network-reachable and requires no authentication or user interaction.

Critical Impact

Remote unauthenticated attackers can trigger a denial-of-service condition on affected D-Link DI-8003 routers by sending a malformed pid parameter to /trace.asp.

Affected Products

• D-Link DI-8003 hardware
• D-Link DI-8003 firmware version 16.07.26A1
• Networks operating the DI-8003 as an edge or gateway router

Discovery Timeline

• 2026-04-08 - CVE-2025-50657 published to NVD
• 2026-04-22 - Last updated in NVD database

Technical Details for CVE-2025-50657

Vulnerability Analysis

The DI-8003 web management interface exposes the /trace.asp endpoint, which accepts a pid parameter as input. The handler copies the supplied value into a fixed-size stack buffer without validating its length. An attacker who submits an oversized pid value overflows the buffer and corrupts adjacent stack data, including saved return addresses. The corrupted stack frame causes the HTTP server process to crash, rendering the router's management plane and routing functions unavailable until reboot.

The vulnerability is categorized as a stack-based buffer overflow [CWE-121]. While the public advisory documents availability impact only, stack buffer overflows in embedded MIPS or ARM firmware can sometimes be leveraged for control-flow hijacking when memory protections such as ASLR or stack canaries are absent. Confirmed impact in the public record is limited to denial of service.

Root Cause

The root cause is the absence of length validation on the pid query parameter before it is copied into a stack-allocated buffer in the /trace.asp request handler. The firmware lacks bounds checking on attacker-controlled input, a common pattern in embedded SOHO router web interfaces written in C.

Attack Vector

An attacker reaches the vulnerable endpoint over the network by issuing a single HTTP request to the DI-8003 management interface. No credentials, prior session, or user interaction are required. Devices exposing the management interface to the internet or to untrusted internal segments are directly reachable. The exploitation primitive is a malformed request to /trace.asp carrying an oversized pid value, which crashes the embedded web server. Public proof-of-concept exploit code is not currently listed in ExploitDB, and the vulnerability is not on the CISA KEV list. Refer to the D-Link Security Advisory SAP10505 for vendor technical details.

Detection Methods for CVE-2025-50657

Indicators of Compromise

• HTTP requests to /trace.asp containing abnormally long pid parameter values in web server or proxy logs
• Unexpected reboots, crashes, or restarts of the DI-8003 HTTP daemon
• Loss of management plane availability following inbound HTTP traffic from external sources
• Repeated short-interval connection attempts to TCP ports hosting the DI-8003 web administration interface

Detection Strategies

• Inspect HTTP request logs at upstream firewalls or reverse proxies for GET or POST requests targeting /trace.asp with parameter lengths exceeding typical values (for example, more than 64 bytes)
• Deploy network IDS signatures that flag HTTP requests to D-Link administration paths originating from untrusted networks
• Correlate router uptime resets with inbound traffic to the management interface using SNMP or syslog telemetry

Monitoring Recommendations

• Forward router syslog and crash dumps to a centralized logging platform for retention and alerting
• Alert on any external source IP reaching the DI-8003 management interface
• Track HTTP parameter length anomalies for endpoints exposed by SOHO and branch routers

How to Mitigate CVE-2025-50657

Immediate Actions Required

• Restrict access to the DI-8003 web management interface to trusted management VLANs only and block external access at the perimeter
• Disable remote (WAN-side) administration on the DI-8003 if it is currently enabled
• Monitor the D-Link Security Bulletin and advisory SAP10505 for firmware updates and apply them when available
• Inventory all DI-8003 devices running firmware 16.07.26A1 across the environment

Patch Information

At the time of publication, D-Link has issued security advisory SAP10505 acknowledging the issue. Administrators should consult the D-Link Security Bulletin for the latest firmware release notes and apply any updated firmware as soon as it is published. Additional technical details are tracked in the GitHub IoT Vulnerability Collection.

Workarounds

• Place the DI-8003 behind an upstream firewall and filter inbound HTTP and HTTPS traffic to the management interface
• Apply ACLs that permit administrative access only from designated management hosts
• If the device is end-of-life or no patched firmware is available, plan replacement with a supported router model

# Example: block external access to the DI-8003 management interface on an upstream Linux firewall
iptables -A FORWARD -p tcp -d <DI-8003-IP> --dport 80  -m iprange ! --src-range 10.0.0.0-10.0.0.255 -j DROP
iptables -A FORWARD -p tcp -d <DI-8003-IP> --dport 443 -m iprange ! --src-range 10.0.0.0-10.0.0.255 -j DROP