CVE-2020-26928
📋 TL;DR
This CVE describes an authentication bypass vulnerability affecting specific NETGEAR WiFi systems. Attackers can bypass authentication mechanisms to gain unauthorized access to device administration interfaces. Affected devices include NETGEAR CBR40, RBK752, RBR750, RBS750, RBK852, RBR850, and RBS850 models.
💻 Affected Systems
- NETGEAR CBR40
- NETGEAR RBK752
- NETGEAR RBR750
- NETGEAR RBS750
- NETGEAR RBK852
- NETGEAR RBR850
- NETGEAR RBS850
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full administrative control of affected NETGEAR devices, allowing attackers to reconfigure network settings, intercept traffic, install malware, or use devices as pivot points into internal networks.
Likely Case
Unauthorized access to device administration interfaces leading to network configuration changes, potential credential theft, and network disruption.
If Mitigated
Limited impact if devices are behind firewalls with restricted administrative access and network segmentation.
🎯 Exploit Status
Authentication bypass vulnerabilities typically have low exploitation complexity. No public proof-of-concept has been identified, but the high CVSS score suggests significant risk.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: CBR40: 2.5.0.10; RBK752/RBR750/RBS750: 3.2.15.25; RBK852/RBR850/RBS850: 3.2.10.11
Vendor Advisory: https://kb.netgear.com/000062324/Security-Advisory-for-Authentication-Bypass-on-Some-WiFi-Systems-PSV-2020-0027
Restart Required: Yes
Instructions:
1. Log into NETGEAR device administration interface. 2. Navigate to firmware update section. 3. Check for and install the latest firmware version. 4. Reboot device after update completes.
🔧 Temporary Workarounds
Restrict administrative access
allLimit administrative interface access to specific trusted IP addresses only
Disable remote administration
allTurn off remote administration features if not required
🧯 If You Can't Patch
- Isolate affected devices in separate network segments with strict firewall rules
- Implement network monitoring for unauthorized access attempts to device administration interfaces
🔍 How to Verify
Check if Vulnerable:
Check device firmware version via administration interface and compare against patched versions listed in advisoryCheck Version:
Log into device web interface and check firmware version in Administration or Advanced settingsVerify Fix Applied:
Confirm firmware version matches or exceeds patched versions: CBR40 >= 2.5.0.10, RBK752/RBR750/RBS750 >= 3.2.15.25, RBK852/RBR850/RBS850 >= 3.2.10.11📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful access
- Administrative access from unexpected IP addresses
- Configuration changes without authorized user activity
Network Indicators:
- Unusual traffic patterns to device administration ports (typically 80, 443, 8080)
- Administrative interface access from external IPs if remote admin is disabled
SIEM Query:
source_ip=external AND (dest_port=80 OR dest_port=443 OR dest_port=8080) AND dest_ip=NETGEAR_device AND http_status=200