CVE-2025-9443
📋 TL;DR
A buffer overflow vulnerability in Tenda CH22 routers allows remote attackers to execute arbitrary code by manipulating the new_account parameter in the formeditUserName function. This affects Tenda CH22 routers running firmware version 1.0.0.1. Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- Tenda CH22
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, credential theft, network pivoting, and persistent backdoor installation.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept traffic, or use the device as part of a botnet.
If Mitigated
Denial of service or limited information disclosure if exploit fails to achieve code execution.
🎯 Exploit Status
Exploit code is publicly available on GitHub. Attack requires sending crafted HTTP POST request to /goform/editUserName 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. 3. Log into router admin interface. 4. Navigate to firmware upgrade section. 5. Upload and apply new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to router web interface
Login to router admin > Advanced Settings > Remote Management > Disable
Network segmentation
allIsolate router management interface to trusted network
Configure firewall rules to restrict access to router IP on ports 80,443,8080
🧯 If You Can't Patch
- Replace affected routers with different models that receive security updates
- Implement strict network access controls to limit exposure of router management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface or via command: curl -s http://router-ip/ | grep -i 'CH22'Check Version:
curl -s http://router-ip/status.asp | grep -o 'FW_VERSION=[^&]*'Verify Fix Applied:
Verify firmware version is no longer 1.0.0.1 and test if /goform/editUserName endpoint rejects malformed new_account parameter📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /goform/editUserName with unusually long new_account parameter
- Router crash/reboot logs
- Unusual process execution in router logs
Network Indicators:
- HTTP traffic to router port 80/443 with POST to /goform/editUserName containing buffer overflow patterns
- Unusual outbound connections from router
SIEM Query:
source="router_logs" AND (uri_path="/goform/editUserName" AND method="POST" AND content_length>100)