CVE-2022-26641
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on TP-LINK TL-WR840N routers via a buffer overflow in the httpRemotePort parameter. Attackers can potentially take full control of affected devices. Only TP-LINK TL-WR840N(ES)_V6.20 routers are affected.
💻 Affected Systems
- TP-LINK TL-WR840N
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to persistent backdoor installation, network traffic interception, and lateral movement to other devices on the network.
Likely Case
Router compromise allowing attackers to modify DNS settings, intercept traffic, or use the device as part of a botnet.
If Mitigated
Limited impact if device is behind firewall with restricted inbound access and regular monitoring.
🎯 Exploit Status
Proof-of-concept available in GitHub repository. Exploitation requires sending specially crafted HTTP requests to the router's web interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check TP-LINK support site for firmware updates
2. If update available, download and install via web interface
3. Reboot router after installation
🔧 Temporary Workarounds
Disable Remote Management
allPrevents external exploitation by disabling remote access to router web interface
Network Segmentation
allPlace router on isolated network segment to limit potential damage
🧯 If You Can't Patch
- Replace affected router with updated model
- Implement strict firewall rules blocking all inbound traffic to router management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface under System Tools > Firmware UpgradeCheck Version:
Not applicable - check via web interfaceVerify Fix Applied:
Verify firmware version is different from V6.20 after update📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to router management interface
- Multiple failed login attempts followed by buffer overflow patterns
Network Indicators:
- HTTP requests with malformed httpRemotePort parameter to router IP
- Unusual outbound traffic from router
SIEM Query:
source_ip="router_ip" AND http_request CONTAINS "httpRemotePort" AND http_request LENGTH > 100