CVE-2025-6138
📋 TL;DR
A critical buffer overflow vulnerability in TOTOLINK T10 routers allows remote attackers to execute arbitrary code by sending specially crafted HTTP POST requests to the setWizardCfg function. This affects TOTOLINK T10 routers running firmware version 4.1.8cu.5207. Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- TOTOLINK T10
📦 What is this software?
T10 Firmware by Totolink
⚠️ 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
Limited impact if devices are behind firewalls with strict inbound filtering, though internal exploitation remains possible.
🎯 Exploit Status
Public exploit details are available, making weaponization likely. The vulnerability requires no authentication and has straightforward exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.totolink.net/
Restart Required: Yes
Instructions:
1. Check TOTOLINK website for firmware updates. 2. Download latest firmware for T10 model. 3. Upload via router admin interface. 4. Reboot router after update.
🔧 Temporary Workarounds
Network Segmentation
allIsolate TOTOLINK T10 routers in separate network segments with strict firewall rules.
Access Control Lists
allImplement ACLs to restrict HTTP access to router management interface from trusted IPs only.
🧯 If You Can't Patch
- Replace affected TOTOLINK T10 routers with different models that are not vulnerable.
- Implement strict network monitoring and intrusion detection for suspicious HTTP POST requests to router IPs.
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via admin interface. If version is 4.1.8cu.5207, device is vulnerable.Check Version:
Login to router admin interface and check System Status or Firmware Version page.Verify Fix Applied:
After updating firmware, verify version is no longer 4.1.8cu.5207 and test that HTTP POST requests to /cgi-bin/cstecgi.cgi with large ssid5g parameters are rejected.📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /cgi-bin/cstecgi.cgi with unusually large ssid5g parameter values
- Router crash/restart logs
Network Indicators:
- HTTP traffic to router IP on port 80/443 with POST method to cgi-bin path
- Unusual outbound connections from router IP
SIEM Query:
source_ip="router_ip" AND http_method="POST" AND http_uri="/cgi-bin/cstecgi.cgi" AND http_param="ssid5g" AND http_param_size>1000🔗 References
- https://candle-throne-f75.notion.site/TOTOLINK-T10-setWizardCfg-20ddf0aa1185808892f1dbbf63e6a153?pvs=73
- https://vuldb.com/?ctiid.312607
- https://vuldb.com/?id.312607
- https://vuldb.com/?submit.592917
- https://www.totolink.net/
- https://candle-throne-f75.notion.site/TOTOLINK-T10-setWizardCfg-20ddf0aa1185808892f1dbbf63e6a153
