CVE-2021-45611
📋 TL;DR
This CVE describes a critical buffer overflow vulnerability in multiple NETGEAR router models that allows unauthenticated remote attackers to execute arbitrary code. The vulnerability affects specific firmware versions of listed NETGEAR devices. Attackers can exploit this without any authentication, making it particularly dangerous.
💻 Affected Systems
- NETGEAR DC112A
- NETGEAR R6400
- NETGEAR RAX200
- NETGEAR WNDR3400v3
- NETGEAR XR300
- NETGEAR R8500
- NETGEAR RAX75
- NETGEAR R8300
- NETGEAR RAX80
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attacker to install persistent malware, intercept all network traffic, pivot to internal networks, and potentially brick the device.
Likely Case
Remote code execution leading to device takeover, network traffic interception, and potential lateral movement to connected devices.
If Mitigated
No impact if patched or if devices are behind proper network segmentation and firewalls.
🎯 Exploit Status
Buffer overflow vulnerabilities in network devices are frequently weaponized. The unauthenticated nature and high CVSS score make this attractive to attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: DC112A 1.0.0.52+, R6400 1.0.1.68+, RAX200 1.0.3.106+, WNDR3400v3 1.0.1.38+, XR300 1.0.3.68+, R8500 1.0.2.144+, RAX75 1.0.3.106+, R8300 1.0.2.144+, RAX80 1.0.3.106+
Vendor Advisory: https://kb.netgear.com/000064488/Security-Advisory-for-Pre-Authentication-Buffer-Overflow-on-Some-Routers-PSV-2020-0323
Restart Required: Yes
Instructions:
1. Log into router admin interface. 2. Navigate to Advanced > Administration > Firmware Update. 3. Check for updates and install latest firmware. 4. Reboot router after update completes.
🔧 Temporary Workarounds
Network Segmentation
allPlace routers behind firewalls and restrict WAN access to management interfaces.
Disable Remote Management
allTurn off remote management features if not required.
🧯 If You Can't Patch
- Replace affected devices with patched models or different vendors
- Implement strict network segmentation and firewall rules to limit exposure
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under Advanced > Administration > Firmware UpdateCheck Version:
Router-specific: Log into web interface and check firmware versionVerify Fix Applied:
Confirm firmware version matches or exceeds patched versions listed in advisory📡 Detection & Monitoring
Log Indicators:
- Unusual buffer overflow errors in router logs
- Multiple failed exploit attempts
- Unexpected firmware or configuration changes
Network Indicators:
- Unusual traffic patterns to router management interfaces
- Exploit payload patterns in network traffic
SIEM Query:
source="router_logs" AND ("buffer overflow" OR "segmentation fault" OR "memory violation")