CVE-2025-71020
📋 TL;DR
Tenda AX-1806 routers running firmware v1.0.0.1 contain a stack overflow vulnerability in the security parameter handling. Attackers can exploit this by sending specially crafted requests to cause a Denial of Service (DoS), potentially crashing the router. This affects all users of Tenda AX-1806 routers with the vulnerable firmware version.
💻 Affected Systems
- Tenda AX-1806
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router crash requiring physical power cycle, disrupting all network connectivity for connected devices.
Likely Case
Router becomes unresponsive, requiring reboot to restore functionality, causing temporary network outage.
If Mitigated
If router is behind firewall with restricted WAN access, risk is limited to internal attackers only.
🎯 Exploit Status
Public GitHub repository contains proof-of-concept code. Exploitation requires network access to router management interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: Yes
Instructions:
1. Check Tenda official website for firmware updates
2. If update available, download and install via router web interface
3. Reboot router after installation
🔧 Temporary Workarounds
Restrict Management Interface Access
allLimit access to router management interface to trusted IP addresses only
Disable Remote Management
allTurn off remote management features if not required
🧯 If You Can't Patch
- Replace router with different model or vendor
- Place router behind additional firewall with strict access controls
🔍 How to Verify
Check if Vulnerable:
Access router web interface at 192.168.0.1, navigate to System Status or About page, check firmware versionCheck Version:
curl -s http://192.168.0.1/ | grep -i firmware || wget -qO- http://192.168.0.1/ | grep -i firmwareVerify Fix Applied:
Verify firmware version is no longer v1.0.0.1 after update📡 Detection & Monitoring
Log Indicators:
- Router crash/reboot events
- Multiple malformed requests to management interface
- Unusual traffic patterns to router IP
Network Indicators:
- Multiple TCP packets with malformed payloads to router port 80/443
- Sudden drop in router responsiveness
SIEM Query:
source="router_logs" AND (event_type="crash" OR event_type="reboot") OR dest_ip="router_ip" AND (http_user_agent="malicious" OR payload_size>threshold)