CVE-2025-6112
📋 TL;DR
A critical buffer overflow vulnerability in Tenda FH1205 routers allows remote attackers to execute arbitrary code by manipulating the lanMask parameter in the fromadvsetlanip function. This affects Tenda FH1205 routers running firmware version 2.0.0.7. Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- Tenda FH1205
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, lateral movement into internal networks, persistent backdoor installation, and botnet recruitment.
Likely Case
Remote code execution allowing attackers to reconfigure the router, intercept network traffic, or use the device as a pivot point for further attacks.
If Mitigated
Limited impact if device is behind firewall with restricted WAN access, though internal threats could still exploit it.
🎯 Exploit Status
Exploit details have been publicly disclosed, making weaponization highly probable. The vulnerability requires no authentication.
🛠️ 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 FH1205. 3. Access router admin interface. 4. Navigate to firmware upgrade section. 5. Upload and apply the new firmware. 6. Reboot the router.
🔧 Temporary Workarounds
Disable remote administration
allPrevent external access to the vulnerable interface by disabling remote administration features.
Network segmentation
allIsolate affected routers in a separate network segment with strict firewall rules.
🧯 If You Can't Patch
- Replace affected devices with patched or alternative models
- Implement strict network access controls to limit exposure to the vulnerable interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via admin interface. If version is 2.0.0.7, the device is vulnerable.Check Version:
Check via router web interface or SSH if available: cat /proc/version or similar firmware version commandsVerify Fix Applied:
After firmware update, verify the version is no longer 2.0.0.7 and test that the /goform/AdvSetLanip endpoint properly validates input.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/AdvSetLanip with malformed lanMask parameters
- Router crash or reboot logs
- Unusual configuration changes
Network Indicators:
- Exploit traffic patterns to router's web interface on port 80/443
- Unusual outbound connections from router
SIEM Query:
source="router_logs" AND (uri="/goform/AdvSetLanip" AND (lanMask CONTAINS "malformed_pattern" OR request_size > threshold))