CVE-2025-71021
📋 TL;DR
Tenda AX-1806 routers running firmware v1.0.0.1 contain a stack overflow vulnerability in the serverName parameter that allows attackers to crash the device via specially crafted requests. This affects all users of this specific router model and firmware version. The vulnerability enables remote denial of service attacks.
💻 Affected Systems
- Tenda AX-1806
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device crash requiring physical power cycle, potentially leading to extended network downtime and service disruption.
Likely Case
Router becomes unresponsive, requiring reboot and causing temporary network outage for connected devices.
If Mitigated
With proper network segmentation and access controls, impact limited to isolated network segments.
🎯 Exploit Status
Proof of concept available in GitHub repository. Exploitation requires sending crafted request to vulnerable parameter.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: No
Instructions:
Check Tenda official website for firmware updates. If available, download latest firmware and apply through router web interface.
🔧 Temporary Workarounds
Network Segmentation
allIsolate router management interface from untrusted networks
Access Control Lists
allRestrict access to router management interface to trusted IPs only
🧯 If You Can't Patch
- Replace vulnerable router with updated model or different vendor
- Implement network monitoring for DoS attempts against router
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface (typically under System Status or About)Check Version:
Check router web interface or use nmap/router scanning toolsVerify Fix Applied:
Verify firmware version has been updated from v1.0.0.1📡 Detection & Monitoring
Log Indicators:
- Router crash/reboot events
- Unusual requests to management interface
Network Indicators:
- Multiple crafted requests to router management port
- Sudden loss of router connectivity
SIEM Query:
source="router_logs" AND (event="crash" OR event="reboot") OR dest_port=80 AND uri_contains="serverName" AND length>threshold