CVE-2025-50672: Dlink Di-8003 Buffer Overflow Vulnerability

CVE-2025-50672 Overview

CVE-2025-50672 is a buffer overflow vulnerability in D-Link DI-8003 routers running firmware version 16.07.26A1. The flaw resides in the /yyxz_dlink.asp endpoint, which improperly handles parameter input. Remote attackers can send crafted requests over the network without authentication to trigger the overflow and cause a denial-of-service condition on the affected device.

The vulnerability is tracked under CWE-120 (Classic Buffer Overflow). The flaw impacts availability only, with no confidentiality or integrity loss reported.

Critical Impact

Unauthenticated remote attackers can crash the D-Link DI-8003 router by sending malformed parameters to the /yyxz_dlink.asp web endpoint, disrupting network availability.

Affected Products

• D-Link DI-8003 router hardware
• D-Link DI-8003 firmware version 16.07.26A1
• Deployments exposing the device web management interface over untrusted networks

Discovery Timeline

• 2026-04-08 - CVE-2025-50672 published to NVD
• 2026-04-10 - Last updated in NVD database

Technical Details for CVE-2025-50672

Vulnerability Analysis

The vulnerability stems from improper bounds checking in the web management interface of the D-Link DI-8003 router. The /yyxz_dlink.asp endpoint accepts user-supplied parameters and copies them into a fixed-size stack or heap buffer without validating input length. When an attacker submits an oversized parameter value, adjacent memory is overwritten, corrupting program state and crashing the HTTP server process.

The attack requires no authentication and no user interaction. Any attacker who can reach the router web interface over the network can trigger the condition. The result is loss of management plane availability and, in many cases, loss of routing functionality until the device is restarted.

While the public scoring indicates availability impact only, buffer overflows of this class can sometimes be developed into code execution primitives. Administrators should treat the issue as a precursor risk rather than a pure denial-of-service bug.

Root Cause

The root cause is missing input validation in the ASP handler for /yyxz_dlink.asp. The handler copies parameter data into a fixed-length buffer using an unsafe string operation that does not enforce a maximum length. This is a textbook CWE-120 condition common in embedded HTTP daemons compiled against minimal C runtime libraries.

Attack Vector

Exploitation is network-based. An attacker sends a single HTTP request to the router web interface with an oversized parameter value targeting /yyxz_dlink.asp. Devices with the web interface exposed to the internet face the highest risk, but lateral attackers inside a LAN can also reach the management endpoint.

No public proof-of-concept exploit is currently listed in CISA KEV or Exploit-DB. Technical details are documented in the GitHub IoT Vulnerability Collection.

Detection Methods for CVE-2025-50672

Indicators of Compromise

• Unexpected reboots or crashes of the D-Link DI-8003 router web management daemon
• HTTP requests to /yyxz_dlink.asp containing abnormally long parameter values
• Loss of management interface responsiveness following inbound HTTP traffic from untrusted sources
• Repeated TCP connections to the router HTTP/HTTPS management ports from a single external source

Detection Strategies

• Inspect web server and router system logs for crash events correlated with requests to /yyxz_dlink.asp
• Deploy network intrusion detection signatures that flag HTTP requests with parameter values exceeding reasonable length thresholds against the /yyxz_dlink.asp URI
• Monitor for repeated connection resets or service restarts on TCP ports hosting the router management interface

Monitoring Recommendations

• Forward router syslog output to a central logging or SIEM platform and alert on daemon restart events
• Track inbound traffic to router management interfaces and alert on connections sourced from outside the management network
• Audit firmware versions across the fleet to identify devices still running 16.07.26A1

How to Mitigate CVE-2025-50672

Immediate Actions Required

• Restrict access to the DI-8003 web management interface so that only trusted management subnets can reach it
• Disable WAN-side access to the router administrative interface if it is currently exposed
• Inventory all DI-8003 devices and confirm whether they are running the affected firmware build 16.07.26A1
• Monitor the D-Link Security Bulletin for a firmware update addressing CVE-2025-50672

Patch Information

At the time of publication, no fixed firmware version has been confirmed in the NVD record. Administrators should consult the D-Link Security Bulletin for the latest vendor guidance and apply any firmware update for the DI-8003 series as soon as it becomes available.

Workarounds

• Place the router management interface behind a firewall ACL that permits only specific administrator IP addresses
• Disable remote management (WAN-side HTTP/HTTPS) on the DI-8003 until a fixed firmware release is available
• Segment IoT and network infrastructure devices onto a dedicated management VLAN with no direct access from user endpoints
• Replace end-of-support D-Link DI-8003 devices with currently supported models where a vendor patch is not forthcoming

# Example: restrict router management access using an upstream firewall (iptables)
# Allow only the management subnet 10.10.0.0/24 to reach the router admin interface
iptables -A FORWARD -p tcp -d <ROUTER_IP> --dport 80  -s 10.10.0.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d <ROUTER_IP> --dport 443 -s 10.10.0.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d <ROUTER_IP> --dport 80  -j DROP
iptables -A FORWARD -p tcp -d <ROUTER_IP> --dport 443 -j DROP