CVE-2025-64053
📋 TL;DR
A buffer overflow vulnerability in Fanvil x210 VoIP phones running firmware 2.12.20 allows attackers to cause denial of service or potentially execute arbitrary code via specially crafted POST requests to the web configuration endpoint. This affects organizations using these devices for telephony services.
💻 Affected Systems
- Fanvil x210 VoIP Phone
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, lateral movement to internal networks, and persistent backdoor installation.
Likely Case
Denial of service causing phone functionality disruption and potential device reboot/crash.
If Mitigated
Limited impact if devices are behind firewalls with restricted web interface access.
🎯 Exploit Status
Exploit requires crafting specific HTTP POST requests to vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: http://fanvil.com
Restart Required: No
Instructions:
1. Check Fanvil website for security advisories
2. Monitor for firmware updates
3. Apply patches when available
🔧 Temporary Workarounds
Disable Web Configuration Interface
allDisable the web management interface to prevent exploitation
Access phone web interface > System > Network > Web Server > Disable
Network Segmentation
allIsolate VoIP phones in separate VLAN with restricted access
🧯 If You Can't Patch
- Implement strict firewall rules blocking external access to port 80/443 on VoIP devices
- Deploy network intrusion detection to monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface: System > Status > VersionCheck Version:
curl -s http://device-ip/cgi-bin/webconfig?page=status | grep FirmwareVerify Fix Applied:
Verify firmware version is updated beyond 2.12.20📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to /cgi-bin/webconfig?page=upload&action=submit
- Device reboot/crash logs
- Unusual process execution
Network Indicators:
- HTTP POST requests with large payloads to vulnerable endpoint
- Traffic patterns indicating buffer overflow attempts
SIEM Query:
source="voip-firewall" AND dest_port=80 AND uri="/cgi-bin/webconfig?page=upload&action=submit" AND method="POST"