CVE-2021-45656
📋 TL;DR
This CVE describes a server-side injection vulnerability in multiple NETGEAR router and WiFi system models, allowing attackers to execute arbitrary code or commands on affected devices. It impacts users running firmware versions below specified thresholds, potentially compromising network security and device integrity.
💻 Affected Systems
- NETGEAR D6200
- D7000
- R6020
- R6080
- R6050
- JR6150
- R6120
- R6220
- R6230
- R6260
- R6800
- R6900v2
- R6700v2
- R7450
- AC2100
- AC2400
- AC2600
- RBK40
- RBR40
- RBS40
- RBK20
- RBR20
- RBS20
- RBK50
- RBR50
- RBS50
- RBS50Y
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full device compromise leading to remote code execution, data theft, network eavesdropping, or use as a botnet node.
Likely Case
Unauthorized access to device settings, network disruption, or credential harvesting from connected devices.
If Mitigated
Limited impact if isolated or patched, but could still allow local network attacks if exploited internally.
🎯 Exploit Status
Based on CWE-74 (Injection) and CVSS 7.1, exploitation likely requires some technical skill but no authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: See affected_systems.versions for minimum fixed versions per model.
Vendor Advisory: https://kb.netgear.com/000064066/Security-Advisory-for-Server-Side-Injection-on-Some-Routers-and-WiFi-Systems-PSV-2019-0140
Restart Required: Yes
Instructions:
1. Log into the NETGEAR router admin interface via web browser. 2. Navigate to Advanced > Administration > Firmware Update. 3. Check for updates and install the latest firmware version listed in the advisory. 4. Reboot the device after update.
🔧 Temporary Workarounds
Disable remote management
allPrevents external access to the router's admin interface, reducing attack surface.
Network segmentation
allIsolate affected devices on a separate VLAN to limit potential lateral movement.
🧯 If You Can't Patch
- Replace affected devices with updated models or alternative brands.
- Implement strict network access controls and monitor for suspicious activity.
🔍 How to Verify
Check if Vulnerable:
Access router admin interface, go to Advanced > Administration > Firmware Update, and compare current version with patched versions listed in the advisory.Check Version:
No CLI command; check via web interface at http://routerlogin.net or IP address.Verify Fix Applied:
Confirm firmware version matches or exceeds the patched version for your model after update.📡 Detection & Monitoring
Log Indicators:
- Unusual admin login attempts
- Unexpected firmware changes
- Suspicious network traffic from router IP
Network Indicators:
- Anomalous outbound connections from router
- Port scans originating from internal network
SIEM Query:
Example: source_ip="router_ip" AND (event_type="authentication_failure" OR event_type="firmware_update")