CVE-2021-45617
📋 TL;DR
This vulnerability allows unauthenticated attackers to execute arbitrary commands on affected NETGEAR devices via command injection. It affects multiple NETGEAR routers, extenders, and WiFi systems running vulnerable firmware versions. Attackers can exploit this remotely without any authentication.
💻 Affected Systems
- NETGEAR CBR40
- EAX20
- EAX80
- EX7500
- R6400
- R6900P
- R7000
- R7000P
- R7900
- R7960P
- R8000
- RAX200
- RS400
- XR300
- MK62
- MR60
- R6400v2
- R8000P
- RAX20
- RAX45
- RAX80
- MS60
- R6700v3
- R7900P
- RAX15
- RAX50
- RAX75
- RBR750
- RBR850
- RBS750
- RBS850
- RBK752
- RBK852
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attackers to install persistent malware, pivot to internal networks, intercept all network traffic, and use the device as part of a botnet.
Likely Case
Remote code execution leading to device takeover, network traffic interception, credential theft, and lateral movement to other devices on the network.
If Mitigated
No impact if devices are patched or properly segmented behind firewalls with restricted WAN access.
🎯 Exploit Status
Public exploit code exists for this vulnerability. The CVSS score of 9.8 indicates critical severity with low attack complexity.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions specified in the CVE description (e.g., CBR40 2.5.0.24+, EAX20 1.0.0.48+, etc.)
Vendor Advisory: https://kb.netgear.com/000064505/Security-Advisory-for-Pre-Authentication-Command-Injection-on-Some-Routers-Extenders-and-WiFi-Systems-PSV-2020-0156
Restart Required: Yes
Instructions:
1. Log into NETGEAR router admin interface. 2. Navigate to Advanced > Administration > Firmware Update. 3. Check for updates and install the latest firmware. 4. Reboot the device after update completes.
🔧 Temporary Workarounds
Disable remote management
allDisable remote management/WAN access to the router admin interface
Network segmentation
allPlace affected devices behind a firewall with strict inbound rules
🧯 If You Can't Patch
- Replace affected devices with patched models or different vendors
- Implement strict network segmentation and firewall rules to limit device exposure
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router admin interface under Advanced > Administration > Firmware UpdateCheck Version:
No CLI command - check via web interface at router IP addressVerify Fix Applied:
Verify firmware version matches or exceeds the patched versions listed in the CVE description📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in system logs
- Multiple failed authentication attempts followed by successful command execution
- Unexpected system reboots or configuration changes
Network Indicators:
- Unusual outbound connections from router
- Traffic to known malicious IPs from router
- Unexpected open ports on router
SIEM Query:
source="router_logs" AND (command_injection OR shell_exec OR system_call) AND NOT user=authenticated