CVE-2025-12211
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on Tenda O3 routers via a stack-based buffer overflow in the DMZ configuration function. Attackers can exploit this flaw without authentication to potentially take full control of affected devices. All users running Tenda O3 firmware version 1.0.0.10(2478) are affected.
💻 Affected Systems
- Tenda O3 router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to persistent backdoor installation, network traffic interception, lateral movement to other devices, and botnet recruitment.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept traffic, or use the device as a pivot point for further attacks.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering, though internal network compromise remains possible.
🎯 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. Download latest firmware 3. Access router admin interface 4. Upload and install firmware update 5. Reboot router
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to router administration interface
Network segmentation
allIsolate router management interface to separate VLAN
🧯 If You Can't Patch
- Replace affected devices with patched or alternative models
- Implement strict network access controls to limit exposure to router management interface
🔍 How to Verify
Check if Vulnerable:
Access router web interface, navigate to System Status or About page, check firmware version matches 1.0.0.10(2478)Check Version:
curl -s http://router-ip/goform/getStatus | grep versionVerify Fix Applied:
After firmware update, verify version no longer matches vulnerable version📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/setDmzInfo with long dmzIP parameters
- Multiple failed authentication attempts followed by DMZ configuration changes
Network Indicators:
- Unusual outbound connections from router to unknown IPs
- Traffic patterns suggesting router compromise
SIEM Query:
source="router_logs" AND uri="/goform/setDmzInfo" AND (dmzIP.length>50 OR status=500)