CVE-2026-3399
📋 TL;DR
A buffer overflow vulnerability in Tenda F453 routers allows remote attackers to execute arbitrary code or cause denial of service by sending specially crafted requests to the httpd service. This affects Tenda F453 router users running firmware version 1.0.0.3. The vulnerability is in the DHCP server configuration function and can be exploited without authentication.
💻 Affected Systems
- Tenda F453
📦 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
Denial of service causing router crashes and network disruption, potentially leading to temporary loss of connectivity.
If Mitigated
Limited impact if network segmentation isolates the router and external access is restricted.
🎯 Exploit Status
Public exploit code is available in GitHub repositories. The vulnerability requires sending crafted HTTP requests to the vulnerable endpoint.
🛠️ 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. If available, download the latest firmware. 3. Access router web interface. 4. Navigate to firmware upgrade section. 5. Upload and install the new firmware. 6. Reboot the router.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to the router's web management interface
Network Segmentation
allIsolate the router from untrusted networks and restrict access to management interface
🧯 If You Can't Patch
- Replace affected router with a different model that receives security updates
- Implement strict network access controls to limit who can reach the router's management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface (typically under System Status or About) or via SSH if enabled: cat /proc/versionCheck Version:
Check web interface or use: cat /proc/version | grep -i tendaVerify Fix Applied:
Verify firmware version has been updated to a version later than 1.0.0.3📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to /goform/GstDhcpSetSer
- Router crash/restart logs
- Buffer overflow error messages in system logs
Network Indicators:
- Multiple malformed HTTP requests to router management interface
- Unusual traffic patterns to router port 80/443
SIEM Query:
source="router_logs" AND (uri="/goform/GstDhcpSetSer" OR message="buffer overflow" OR message="segmentation fault")