CVE-2025-13288
📋 TL;DR
A buffer overflow vulnerability in Tenda CH22 routers allows remote attackers to execute arbitrary code by manipulating the 'delno' parameter in the PPTPUserSetting 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, creation of persistent backdoors, lateral movement to internal networks, 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
Denial of service or limited information disclosure if exploit attempts are blocked by network controls.
🎯 Exploit Status
Public exploit code is available on GitHub. The vulnerability requires sending a specially crafted HTTP request to the router's web interface.
🛠️ 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. Download the latest firmware for CH22. 3. Access router admin interface. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install the new firmware. 6. Reboot the router.
🔧 Temporary Workarounds
Disable PPTP functionality
allDisable PPTP VPN service if not required to remove the vulnerable code path.
Restrict management interface access
allConfigure firewall rules to restrict access to the router's web management interface.
🧯 If You Can't Patch
- Isolate affected routers in a separate network segment with strict firewall rules
- Implement network monitoring for exploit attempts targeting the /goform/PPTPUserSetting endpoint
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface: System Status > Firmware Version. If version is 1.0.0.1, the device is vulnerable.Check Version:
curl -s http://router-ip/goform/getStatus | grep versionVerify Fix Applied:
After updating firmware, verify the version is no longer 1.0.0.1 and test that PPTP functionality works without crashing.📡 Detection & Monitoring
Log Indicators:
- HTTP requests to /goform/PPTPUserSetting with abnormal delno parameter values
- Router crash/reboot logs following PPTP configuration attempts
Network Indicators:
- HTTP POST requests to /goform/PPTPUserSetting with long delno parameter values
- Unusual outbound connections from router after exploit attempts
SIEM Query:
source="router_logs" AND uri="/goform/PPTPUserSetting" AND (param="delno" AND length(value)>50)