CVE-2025-5624
📋 TL;DR
This critical vulnerability in D-Link DIR-816 routers allows remote attackers to execute arbitrary code via a stack-based buffer overflow in the QoS configuration function. Attackers can exploit this without authentication to potentially take full control of affected devices. Only unsupported D-Link DIR-816 routers running specific firmware versions are affected.
💻 Affected Systems
- D-Link DIR-816
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing remote code execution, persistent backdoor installation, network traffic interception, and lateral movement to other devices on the network.
Likely Case
Remote attackers gaining administrative access to the router, modifying network settings, intercepting traffic, and using the device as a foothold for further attacks.
If Mitigated
If properly segmented and monitored, impact limited to the router itself with no lateral movement to other systems.
🎯 Exploit Status
Public exploit code is available on GitHub. The vulnerability requires sending specially crafted HTTP requests to the router's web interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: None available
Vendor Advisory: https://www.dlink.com/
Restart Required: No
Instructions:
No official patch is available as this product is end-of-life. The only secure option is to replace the device with a supported model.
🔧 Temporary Workarounds
Disable remote management
allDisable WAN-side access to the router's web management interface
Access router admin panel -> Advanced -> Remote Management -> Disable
Block vulnerable endpoint
linuxUse firewall rules to block access to the vulnerable /goform/QoSPortSetup endpoint
iptables -A INPUT -p tcp --dport 80 -m string --string "/goform/QoSPortSetup" --algo bm -j DROP
🧯 If You Can't Patch
- Immediately replace affected routers with supported models from any vendor
- Segment affected routers on isolated VLANs with strict firewall rules preventing internet access to management interfaces
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin panel (typically at 192.168.0.1 or 192.168.1.1) and verify it matches affected version 1.10CNB05Check Version:
curl -s http://router-ip/ | grep -i firmware || Check web interface manuallyVerify Fix Applied:
No fix available to verify. Replacement with different hardware is the only verification of remediation.📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to /goform/QoSPortSetup with unusually long parameter values
- Router reboot events following suspicious web requests
Network Indicators:
- HTTP requests containing 'port0_group', 'port0_remarker', 'ssid0_group', or 'ssid0_remarker' parameters with excessive length
SIEM Query:
source="router_logs" AND url="/goform/QoSPortSetup" AND (param_length>1000 OR status_code=500)