CVE-2025-45867
📋 TL;DR
This CVE describes a buffer overflow vulnerability in TOTOLINK A3002R routers via the static_dns1 parameter in the formIpv6Setup interface. Attackers can exploit this to potentially execute arbitrary code or crash the device. Only users of TOTOLINK A3002R routers with specific firmware versions are affected.
💻 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
Device crash causing denial of service and network disruption
If Mitigated
Limited impact if device is behind firewall with restricted access to management interface
🎯 Exploit Status
Exploit requires access to the web management interface but authentication status is unclear from available information
🛠️ 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:
1. Check vendor website for firmware updates 2. Download latest firmware 3. Access router web interface 4. Navigate to firmware upgrade section 5. Upload new firmware file 6. Wait for reboot
🔧 Temporary Workarounds
Disable IPv6 Configuration Access
allRestrict access to the IPv6 configuration interface
Network Segmentation
allIsolate router management interface from untrusted networks
🧯 If You Can't Patch
- Disable IPv6 functionality entirely if not needed
- Implement strict firewall rules to block external access to router management interface (ports 80/443)
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface at System Status > Firmware VersionCheck Version:
curl -s http://router-ip/status.cgi | grep firmwareVerify Fix Applied:
Verify firmware version has been updated beyond v4.0.0-B20230531.1404📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /cgi-bin/formIpv6Setup
- Large payloads in static_dns1 parameter
- Router crash/reboot events
Network Indicators:
- Multiple failed authentication attempts followed by large POST payloads
- Traffic patterns matching buffer overflow exploitation
SIEM Query:
source="router.log" AND (uri="/cgi-bin/formIpv6Setup" AND param="static_dns1" AND length>100)