CVE-2026-3808
📋 TL;DR
A stack-based buffer overflow vulnerability in Tenda FH1202 routers allows remote attackers to execute arbitrary code by manipulating the webSiteId parameter. This affects Tenda FH1202 routers running firmware version 1.2.0.14(408). Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- Tenda FH1202
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, enabling attackers to install malware, pivot to internal networks, or create persistent backdoors.
Likely Case
Remote code execution resulting in device takeover, allowing attackers to modify router settings, intercept traffic, or launch attacks against internal networks.
If Mitigated
Denial of service if exploit fails or is detected by security controls, with potential for limited configuration changes.
🎯 Exploit Status
Public exploit code is available on GitHub, making exploitation straightforward for attackers with basic skills.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.tenda.com.cn/
Restart Required: Yes
Instructions:
1. Check Tenda's official website for firmware updates. 2. Download the latest firmware for FH1202. 3. Log into router admin interface. 4. Navigate to firmware upgrade section. 5. Upload and apply the new firmware. 6. Reboot the router.
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to the vulnerable web interface
Log into router admin → System Tools → Remote Management → Disable
Network segmentation
allIsolate affected routers from critical internal networks
Configure firewall rules to restrict router access to management VLAN only
🧯 If You Can't Patch
- Replace affected routers with patched or different models
- Implement strict network access controls and monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via admin interface: System Status → Firmware VersionCheck Version:
curl -s http://router-ip/goform/getStatus | grep versionVerify Fix Applied:
Verify firmware version is no longer 1.2.0.14(408) after update📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/webtypelibrary
- Multiple failed exploitation attempts
- Unexpected router reboots
Network Indicators:
- Traffic to router on unusual ports
- Suspicious payloads in HTTP requests to router management interface
SIEM Query:
source="router_logs" AND uri="/goform/webtypelibrary" AND (method="POST" OR contains(message, "webSiteId"))