CVE-2021-45526
📋 TL;DR
This vulnerability allows an authenticated attacker to trigger a buffer overflow on affected NETGEAR routers and extenders. Successful exploitation could lead to arbitrary code execution or device compromise. Users with specific NETGEAR models running outdated firmware are affected.
💻 Affected Systems
- NETGEAR EX6000
- EX6120
- EX6130
- R6300v2
- R6400
- R7000
- R7900
- R8000
- R7000P
- R8000P
- RAX80
- R6900P
- R7900P
- RAX75
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device takeover with persistent backdoor installation, allowing attacker to intercept network traffic, pivot to internal networks, or launch attacks from the compromised device.
Likely Case
Device crash/reboot causing temporary network disruption, or limited code execution within router context allowing configuration changes.
If Mitigated
No impact if proper authentication controls prevent unauthorized access to administrative interfaces.
🎯 Exploit Status
Requires authentication credentials. Buffer overflow (CWE-120) typically requires specific knowledge of memory layout.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: See vendor advisory for specific version per model (e.g., EX6000 1.0.0.38+)
Vendor Advisory: https://kb.netgear.com/000064446/Security-Advisory-for-Post-Authentication-Buffer-Overflow-on-Some-Routers-and-Extenders-PSV-2019-0078
Restart Required: Yes
Instructions:
1. Identify your NETGEAR model. 2. Visit NETGEAR support site. 3. Download latest firmware for your model. 4. Log into router admin interface. 5. Navigate to firmware update section. 6. Upload and install new firmware. 7. Wait for automatic reboot.
🔧 Temporary Workarounds
Disable remote administration
allPrevents external attackers from accessing administrative interface
Use strong authentication
allImplement complex passwords and consider multi-factor authentication if supported
🧯 If You Can't Patch
- Isolate affected devices on separate network segment
- Implement network monitoring for suspicious administrative access attempts
🔍 How to Verify
Check if Vulnerable:
Check current firmware version in router admin interface under Advanced > Administration > Router Update or similarCheck Version:
No CLI command - check via web interface at http://routerlogin.net or router IP addressVerify Fix Applied:
Confirm firmware version matches or exceeds patched version listed in NETGEAR advisory📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful login
- Unusual administrative access patterns
- Firmware version changes
Network Indicators:
- Unusual outbound connections from router
- Traffic patterns suggesting device compromise
SIEM Query:
source="router_logs" AND (event_type="authentication" AND result="success") AND user!="admin" OR source="router_logs" AND message="buffer overflow"