CVE-2025-25668
📋 TL;DR
This CVE describes a stack overflow vulnerability in Tenda AC8V4 routers that allows remote code execution. Attackers can exploit the shareSpeed parameter in the sub_47D878 function to crash the device or execute arbitrary code. All users running the vulnerable firmware version are affected.
💻 Affected Systems
- Tenda AC8V4
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attacker to install persistent malware, intercept all network traffic, pivot to internal networks, and brick the device.
Likely Case
Router crash requiring physical reset, temporary network outage, or limited code execution allowing traffic monitoring.
If Mitigated
Denial of service if exploit fails or is detected by network monitoring, with minimal impact beyond temporary connectivity loss.
🎯 Exploit Status
GitHub repository contains detailed analysis and likely exploit code. Stack overflow vulnerabilities in embedded devices are commonly weaponized due to their impact.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates
2. If update available, download and verify checksum
3. Access router admin interface
4. Navigate to firmware upgrade section
5. Upload new firmware file
6. Wait for reboot and verify version
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router web interface
Network Segmentation
allIsolate router management interface to separate VLAN
🧯 If You Can't Patch
- Replace router with different model or vendor
- Implement strict firewall rules blocking all external access to router management interface
🔍 How to Verify
Check if Vulnerable:
Access router web interface, navigate to System Status or About page, check firmware version matches V16.03.34.06Check Version:
curl -s http://router-ip/goform/getStatus | grep version or check web interfaceVerify Fix Applied:
After firmware update, verify version is different from V16.03.34.06📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to router management interface
- Multiple connection attempts to router web interface
- Router crash/reboot logs
Network Indicators:
- Unusual traffic patterns to router management port (typically 80/443)
- Exploit-like payloads in HTTP requests
SIEM Query:
source="router_logs" AND (uri_path="/goform/setMacFilterCfg" OR uri_path CONTAINS "shareSpeed")