CVE-2026-3811
📋 TL;DR
A stack-based buffer overflow vulnerability in Tenda FH1202 routers allows remote attackers to execute arbitrary code by manipulating the 'page' parameter in the fromP2pListFilter function. 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, lateral movement to internal networks, persistent backdoor installation, and botnet recruitment.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept network traffic, or use the device as a pivot point for further attacks.
If Mitigated
Limited impact if device is behind firewall with strict inbound filtering and not internet-facing.
🎯 Exploit Status
Public exploit code is available on GitHub, making exploitation trivial 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 website for firmware updates. 2. If update available, download and install via router admin interface. 3. Reboot router after update. 4. Verify firmware version changed from vulnerable version.
🔧 Temporary Workarounds
Network Segmentation
allIsolate affected routers in separate VLANs with strict firewall rules to limit potential lateral movement.
Access Control
linuxBlock external access to router admin interface (port 80/443) at network perimeter.
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Replace vulnerable devices with different models or brands
- Implement strict network monitoring and anomaly detection for affected devices
🔍 How to Verify
Check if Vulnerable:
Access router admin interface and check firmware version under System Status or similar section.Check 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/P2pListFilter
- Multiple failed exploit attempts with varying page parameter values
- Sudden router configuration changes
Network Indicators:
- Unusual outbound connections from router
- Traffic spikes to/from router on non-standard ports
- DNS or routing table modifications
SIEM Query:
source="router.log" AND (uri="/goform/P2pListFilter" OR method="POST" AND uri CONTAINS "P2pListFilter")