CVE-2025-10815
📋 TL;DR
A buffer overflow vulnerability in Tenda AC20 routers allows remote attackers to execute arbitrary code or cause denial of service by sending specially crafted HTTP POST requests. This affects Tenda AC20 routers running firmware up to version 16.03.08.12. The vulnerability is in the SetPptpServerCfg function and can be exploited without authentication.
💻 Affected Systems
- Tenda AC20
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, network infiltration, and persistent backdoor installation.
Likely Case
Router crash causing denial of service, potentially requiring physical reset or firmware reflash.
If Mitigated
Limited impact if device is behind firewall with restricted WAN access and proper network segmentation.
🎯 Exploit Status
Public exploit code available on GitHub. Attack requires sending HTTP POST request to vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.tenda.com.cn/
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates. 2. Download latest firmware for AC20. 3. Access router web interface. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router web interface
Access router web interface > Advanced > System Tools > Remote Management > Disable
Network Segmentation
allIsolate router management interface to trusted network
Configure firewall rules to restrict access to router IP on ports 80,443 to trusted IPs only
🧯 If You Can't Patch
- Replace affected router with supported model
- Implement strict network access controls and monitor for exploit attempts
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface: System Status > Firmware VersionCheck Version:
curl -s http://router-ip/ | grep -i firmwareVerify Fix Applied:
Verify firmware version is above 16.03.08.12 after update📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /goform/SetPptpServerCfg with long startIp parameter
- Router crash/reboot logs
Network Indicators:
- Unusual HTTP traffic to router management interface
- POST requests with buffer overflow patterns
SIEM Query:
source="router_logs" AND (uri="/goform/SetPptpServerCfg" OR message="buffer overflow")