CVE-2025-14526
📋 TL;DR
A buffer overflow vulnerability in Tenda CH22 router firmware version 1.0.0.1 allows remote attackers to execute arbitrary code by manipulating the 'page' parameter in the frmL7ImForm function. This affects all users running the vulnerable firmware version. Remote exploitation is possible without authentication.
💻 Affected Systems
- Tenda CH22
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, network infiltration, data exfiltration, and persistent backdoor installation.
Likely Case
Remote code execution allowing attackers to gain control of the router, modify network settings, intercept traffic, and pivot to internal networks.
If Mitigated
Denial of service or limited impact if network segmentation and proper firewall rules prevent external access to the vulnerable endpoint.
🎯 Exploit Status
Public exploit details are available on GitHub, making exploitation straightforward for attackers with basic skills.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check Tenda's official website for firmware updates. 2. Download the latest firmware for CH22. 3. Access router admin interface. 4. Navigate to firmware upgrade section. 5. Upload and install the new firmware. 6. Reboot the router.
🔧 Temporary Workarounds
Block Access to Vulnerable Endpoint
linuxUse firewall rules to block external access to /goform/L7Im endpoint
iptables -A INPUT -p tcp --dport 80 -m string --string "/goform/L7Im" --algo bm -j DROP
iptables -A INPUT -p tcp --dport 443 -m string --string "/goform/L7Im" --algo bm -j DROP
Disable Remote Management
allTurn off remote administration features to prevent external exploitation
🧯 If You Can't Patch
- Isolate the router in a separate VLAN with strict firewall rules limiting access
- Implement network monitoring and intrusion detection for suspicious traffic to /goform/L7Im
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface. If version is 1.0.0.1, device is vulnerable.Check Version:
curl -s http://router-ip/ | grep -i firmware || Check web interfaceVerify Fix Applied:
After firmware update, verify version number has changed from 1.0.0.1 and test if /goform/L7Im endpoint still responds to buffer overflow attempts.📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to /goform/L7Im with large 'page' parameters
- Unusual process execution or memory errors in router logs
Network Indicators:
- HTTP POST requests to /goform/L7Im with abnormally long parameter values
- Traffic patterns suggesting buffer overflow attempts
SIEM Query:
source="router_logs" AND (url="/goform/L7Im" AND (param_size>1000 OR status_code=500))