CVE-2025-3693
📋 TL;DR
This critical vulnerability in Tenda W12 routers allows remote attackers to execute arbitrary code via a stack-based buffer overflow in the cgiWifiRadioSet function of the /bin/httpd binary. It affects users of Tenda W12 routers running firmware version 3.0.0.5, potentially enabling full device compromise without authentication.
💻 Affected Systems
- Tenda W12
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete router takeover, enabling attackers to intercept traffic, deploy malware, or pivot to internal networks.
Likely Case
Router compromise resulting in denial of service, credential theft, or network eavesdropping.
If Mitigated
Limited impact if isolated from untrusted networks, but still poses risk if exploited internally.
🎯 Exploit Status
Exploit details are publicly disclosed, making it easier for attackers to develop and deploy attacks.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.tenda.com.cn/
Restart Required: Yes
Instructions:
Check Tenda's official website for firmware updates. If available, download and install the latest version via the router's web interface, then reboot the device.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access by disabling remote administration features on the router.
Log into router admin panel, navigate to Advanced Settings > System Tools > Remote Management, and disable it.
Network Segmentation
allIsolate the router from untrusted networks using firewall rules or VLANs.
Configure firewall to block inbound traffic to router management ports (e.g., port 80/443) from external sources.
🧯 If You Can't Patch
- Replace the router with a non-vulnerable model or updated firmware version.
- Implement strict network access controls to limit exposure to only trusted internal IPs.
🔍 How to Verify
Check if Vulnerable:
Access the router's web interface, navigate to System Status or similar, and check the firmware version. If it is 3.0.0.5, the device is vulnerable.Check Version:
curl -s http://router-ip/status.cgi | grep firmware_version or check via web interface.Verify Fix Applied:
After updating, verify the firmware version has changed from 3.0.0.5 to a newer, patched version.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to /cgi-bin/cgiWifiRadioSet endpoint, spikes in buffer overflow errors in system logs.
Network Indicators:
- Anomalous traffic patterns to router management ports from external IPs, especially POST requests with large payloads.
SIEM Query:
source="router_logs" AND (uri="/cgi-bin/cgiWifiRadioSet" OR message="buffer overflow")