CVE-2025-5855
📋 TL;DR
A critical stack-based buffer overflow vulnerability in Tenda AC6 routers allows remote attackers to execute arbitrary code by manipulating the rebootTime parameter. This affects Tenda AC6 routers running firmware version 15.03.05.16. Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- Tenda AC6
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, persistence installation, network pivoting, and data exfiltration
Likely Case
Router takeover for botnet recruitment, DNS hijacking, credential theft, and network surveillance
If Mitigated
Denial of service or limited information disclosure if exploit fails
🎯 Exploit Status
Public exploit details available, making weaponization likely. No authentication required for exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.tenda.com.cn/
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates 2. Download latest firmware 3. Upload via router admin interface 4. Reboot router
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to vulnerable endpoint
Network segmentation
allIsolate AC6 routers from critical network segments
🧯 If You Can't Patch
- Replace vulnerable routers with patched or different models
- Implement strict network ACLs to block access to port 80/443 on affected devices
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface. If version is 15.03.05.16, device is vulnerable.Check Version:
Check via router web interface or SSH if availableVerify Fix Applied:
Verify firmware version has changed from 15.03.05.16 to a newer version📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/SetRebootTimer
- Multiple failed reboot attempts
- Unexpected process crashes
Network Indicators:
- Unusual traffic patterns to router management interface
- Suspicious payloads in HTTP POST requests
SIEM Query:
source="router_logs" AND (uri="/goform/SetRebootTimer" OR process="reboot") AND status="200"