CVE-2025-4268
📋 TL;DR
This vulnerability allows unauthenticated remote attackers to reboot TOTOLINK A720R routers by accessing the /cgi-bin/cstecgi.cgi endpoint with a specific parameter. It affects TOTOLINK A720R routers running firmware version 4.1.5cu.374, exposing them to denial-of-service attacks.
💻 Affected Systems
- TOTOLINK A720R
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could repeatedly reboot routers, causing sustained network outages and disrupting all connected services.
Likely Case
Temporary denial-of-service affecting internet connectivity for all devices behind the router.
If Mitigated
No impact if proper network segmentation and access controls prevent external access to router management interfaces.
🎯 Exploit Status
Exploit requires simple HTTP request to vulnerable endpoint; proof-of-concept code is publicly available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.totolink.net/
Restart Required: Yes
Instructions:
1. Check vendor website for firmware updates. 2. Download latest firmware. 3. Access router admin interface. 4. Upload and apply firmware update. 5. Reboot router.
🔧 Temporary Workarounds
Block External Access
linuxPrevent external access to router management interface using firewall rules.
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
Change Management Port
allChange router's web management port from default to non-standard port.
🧯 If You Can't Patch
- Place router behind firewall with strict inbound rules blocking all access to management ports.
- Disable remote management features in router configuration if enabled.
🔍 How to Verify
Check if Vulnerable:
Send HTTP request to http://[router-ip]/cgi-bin/cstecgi.cgi?topicurl=RebootSystem and check if router reboots without authentication.Check Version:
Check router web interface or use curl -s http://[router-ip]/ | grep -i versionVerify Fix Applied:
Attempt the same request after applying fixes; should receive authentication error or connection refused.📡 Detection & Monitoring
Log Indicators:
- HTTP requests to /cgi-bin/cstecgi.cgi with topicurl=RebootSystem parameter
- Unauthenticated access attempts to router management interface
Network Indicators:
- HTTP GET requests to router IP on port 80/443 with specific parameter
- Sudden router reboots without administrative action
SIEM Query:
source="router.log" AND (uri="/cgi-bin/cstecgi.cgi" AND query="*topicurl=RebootSystem*")