CVE-2025-9014
📋 TL;DR
A remote, unauthenticated attacker can exploit a null pointer dereference vulnerability in the TP-Link TL-WR841N v14 web portal's referer header check to cause denial of service. This affects TL-WR841N v14 routers with firmware versions before 250908, potentially disrupting web portal access for legitimate users.
💻 Affected Systems
- TP-Link TL-WR841N v14
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service for the web portal service, preventing administrative access and requiring physical reset or power cycle to restore functionality.
Likely Case
Temporary web portal service disruption affecting administrative access until the router automatically restarts the service or is manually rebooted.
If Mitigated
No impact if the vulnerability is patched or if the web portal is not exposed to untrusted networks.
🎯 Exploit Status
Exploitation requires sending a malformed HTTP request with a crafted referer header to the web portal interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 250908 or later
Vendor Advisory: https://www.tp-link.com/us/support/faq/4894/
Restart Required: Yes
Instructions:
1. Download firmware version 250908 or later from TP-Link support site. 2. Log into router web portal. 3. Navigate to System Tools > Firmware Upgrade. 4. Upload and install the new firmware. 5. Wait for automatic reboot.
🔧 Temporary Workarounds
Disable Web Portal Access
allDisable remote access to the web portal interface to prevent exploitation from external networks.
Log into router web portal > Security > Remote Management > Disable
Network Segmentation
allRestrict access to the router's web portal to trusted internal networks only using firewall rules.
🧯 If You Can't Patch
- Implement strict network access controls to limit web portal access to trusted IP addresses only
- Monitor router logs for unusual HTTP requests targeting the web portal interface
🔍 How to Verify
Check if Vulnerable:
Check current firmware version in router web portal under System Tools > Firmware Upgrade. If version is below 250908, the device is vulnerable.Check Version:
Check via web portal: System Tools > Firmware UpgradeVerify Fix Applied:
After updating, verify firmware version shows 250908 or higher in System Tools > Firmware Upgrade page.📡 Detection & Monitoring
Log Indicators:
- Web portal service crashes or restarts
- Unusual HTTP requests with malformed referer headers
Network Indicators:
- HTTP requests to router web portal with crafted referer headers
- Sudden loss of web portal connectivity
SIEM Query:
source="router_logs" AND ("web portal" OR "httpd") AND ("crash" OR "restart" OR "referer")