CVE-2025-45862
📋 TL;DR
This CVE describes a buffer overflow vulnerability in TOTOLINK A3002R routers via the interfacenameds parameter in the formDhcpv6s interface. Attackers can exploit this to execute arbitrary code or crash the device. Only users of the affected TOTOLINK A3002R router with the vulnerable firmware are impacted.
💻 Affected Systems
- TOTOLINK A3002R
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, persistence, and lateral movement within the network.
Likely Case
Denial of service causing router crashes and network disruption.
If Mitigated
Limited impact if the vulnerable interface is not exposed or properly segmented.
🎯 Exploit Status
Exploitation requires authentication to the router's web interface. The GitHub reference contains proof-of-concept details.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.totolink.net/home/menu/detail/menu_listtpl/download/id/258/ids/36.html
Restart Required: Yes
Instructions:
Check the vendor's download page for firmware updates. If available, download the latest firmware, log into the router's web interface, navigate to the firmware upgrade section, upload the new firmware file, and apply it. The router will restart automatically.
🔧 Temporary Workarounds
Disable DHCPv6 Server
allTurn off the DHCPv6 server functionality if not required, which may prevent access to the vulnerable interface.
Restrict Management Interface Access
allConfigure firewall rules to limit access to the router's web management interface to trusted IP addresses only.
🧯 If You Can't Patch
- Segment the router on a dedicated network VLAN to limit potential lateral movement.
- Implement network monitoring for unusual traffic patterns or repeated authentication attempts to the router's management interface.
🔍 How to Verify
Check if Vulnerable:
Log into the router's web interface, navigate to System Status or similar, and check the firmware version. If it matches v4.0.0-B20230531.1404, the device is vulnerable.Check Version:
curl -s http://router-ip/status.cgi | grep firmware or check via web interfaceVerify Fix Applied:
After updating firmware, verify the version no longer matches the vulnerable version. Test the formDhcpv6s interface functionality to ensure it operates without crashes.📡 Detection & Monitoring
Log Indicators:
- Repeated authentication failures followed by access to /cgi-bin/cstecgi.cgi with formDhcpv6s parameters
- Router crash/reboot logs
Network Indicators:
- Unusual HTTP POST requests to the router's IP on port 80/443 containing long interfacenameds parameters
SIEM Query:
source="router_logs" AND (url="/cgi-bin/cstecgi.cgi" AND post_data CONTAINS "formDhcpv6s")