CVE-2025-70656
📋 TL;DR
CVE-2025-70656 is a stack overflow vulnerability in Tenda AX-1806 routers that allows attackers to cause Denial of Service (DoS) by sending specially crafted requests to the vulnerable 'mac' parameter. This affects Tenda AX-1806 router users running vulnerable firmware versions. The vulnerability can crash the router's web interface or potentially the entire device.
💻 Affected Systems
- Tenda AX-1806
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router crash requiring physical power cycle, potential remote code execution if the overflow can be controlled to execute arbitrary code, and persistent device unavailability.
Likely Case
Router web interface crash or device reboot, causing temporary network disruption for connected devices until the router restarts automatically or manually.
If Mitigated
Minimal impact with proper network segmentation and firewall rules blocking external access to router management interfaces.
🎯 Exploit Status
The GitHub reference contains technical details and likely proof-of-concept code. Stack overflow vulnerabilities in embedded devices are frequently weaponized due to their impact on network availability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: Yes
Instructions:
1. Check Tenda's official website for firmware updates for AX-1806. 2. Download the latest firmware version. 3. Log into router web interface. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install the new firmware. 6. Wait for router to reboot automatically.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router web interface
Network Segmentation
allIsolate router management interface to trusted network segments only
🧯 If You Can't Patch
- Replace affected Tenda AX-1806 routers with different models or brands that are not vulnerable
- Implement strict firewall rules to block all external access to router management interfaces (ports 80/443)
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface: System Status > Firmware Version. If version is v1.0.0.1, the device is vulnerable.Check Version:
curl -s http://router-ip/ | grep -i firmware || wget -qO- http://router-ip/Verify Fix Applied:
After firmware update, verify version is no longer v1.0.0.1. Test by attempting to access the router interface with normal usage patterns.📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts to router interface
- Router reboot logs without user action
- Web interface crash logs
Network Indicators:
- Unusual traffic to router management ports (80, 443, 8080)
- HTTP requests with malformed MAC addresses in parameters
- Sudden loss of router responsiveness
SIEM Query:
source="router_logs" AND (event="crash" OR event="reboot" OR event="interface_down") OR dest_ip="router_ip" AND (uri="*mac=*" AND uri_length>100)