CVE-2025-25901
📋 TL;DR
A buffer overflow vulnerability in TP-Link TL-WR841ND V11 routers allows attackers to cause Denial of Service (DoS) by sending specially crafted packets to the dnsserver1 and dnsserver2 parameters. This affects users of this specific router model who have not applied security patches. The vulnerability requires network access to the router's web interface.
💻 Affected Systems
- TP-Link TL-WR841ND
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router crash requiring physical reboot, potential remote code execution if buffer overflow can be leveraged for arbitrary code execution (though not confirmed in this CVE).
Likely Case
Router becomes unresponsive, requiring reboot to restore functionality, disrupting network connectivity for all connected devices.
If Mitigated
No impact if router is patched or workarounds are implemented to block exploitation attempts.
🎯 Exploit Status
Exploitation requires crafting specific packets to trigger buffer overflow. No public exploit code available based on provided references.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Latest firmware from TP-Link for TL-WR841ND V11
Vendor Advisory: Check TP-Link security advisories (not provided in CVE references)
Restart Required: Yes
Instructions:
1. Log into router web interface. 2. Navigate to System Tools > Firmware Upgrade. 3. Download latest firmware from TP-Link support site. 4. Upload and apply firmware update. 5. Router will reboot automatically.
🔧 Temporary Workarounds
Disable Remote Management
allPrevents external attackers from accessing router web interface
Navigate to Security > Remote Management in router web interface and disable
Network Segmentation
allIsolate router management interface from untrusted networks
🧯 If You Can't Patch
- Replace router with updated model or different vendor
- Implement strict network access controls to router management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface under System Tools > Firmware UpgradeCheck Version:
No CLI command - check via web interface at 192.168.0.1 or 192.168.1.1Verify Fix Applied:
Verify firmware version matches latest available from TP-Link support site📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts
- Unusual POST requests to /userRpm/WanSlaacCfgRpm.htm
- Router reboot events
Network Indicators:
- Unusual traffic to router management port (typically 80/443)
- Malformed HTTP packets to specific endpoint
SIEM Query:
source_ip="router_ip" AND (url_path="/userRpm/WanSlaacCfgRpm.htm" OR event_type="router_reboot")