CVE-2025-28221
📋 TL;DR
This vulnerability allows remote attackers to crash the web server on Tenda W6_S routers by sending a specially crafted POST request with a malicious time parameter. It affects Tenda W6_S routers running firmware version v1.0.0.4_510. Attackers can exploit this without authentication to cause denial of service.
💻 Affected Systems
- Tenda W6_S
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, though buffer overflow typically causes crashes in this context.
Likely Case
Denial of service through web server crash, disrupting management interface and potentially affecting device functionality.
If Mitigated
Limited to web interface disruption if properly segmented from critical networks.
🎯 Exploit Status
Exploitation requires sending a crafted POST request to the vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Tenda for firmware updates beyond v1.0.0.4_510
Vendor Advisory: Not publicly available
Restart Required: Yes
Instructions:
1. Check Tenda support site for firmware updates. 2. Download latest firmware for W6_S. 3. Upload via web interface. 4. Reboot router.
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to web management interface
Access router settings > Disable 'Remote Management' or similar option
Network segmentation
allIsolate router management interface from untrusted networks
Configure firewall rules to restrict access to router IP on port 80/443
🧯 If You Can't Patch
- Segment router management interface to trusted VLAN only
- Implement network monitoring for abnormal POST requests to router
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface under System Status or similarCheck Version:
Not applicable - check via web interfaceVerify Fix Applied:
Verify firmware version is updated beyond v1.0.0.4_510📡 Detection & Monitoring
Log Indicators:
- Web server crash logs
- Abnormal POST requests to time-related endpoints
Network Indicators:
- Multiple POST requests with long time parameters to router IP
SIEM Query:
source_ip=router_ip AND http_method=POST AND uri CONTAINS 'time' AND content_length>100