CVE-2020-26903
📋 TL;DR
This vulnerability allows attackers to obtain administrative credentials on affected NETGEAR WiFi systems. Attackers can gain full administrative control over the devices, potentially compromising the entire network. The vulnerability affects specific NETGEAR CBR40, RBK752, RBR750, RBS750, RBK852, RBR850, and RBS850 devices running outdated firmware.
💻 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 network compromise: attackers gain administrative access, can reconfigure devices, intercept traffic, install malware, and pivot to other network systems.
Likely Case
Unauthorized administrative access leading to network configuration changes, traffic monitoring, and potential credential theft from connected devices.
If Mitigated
Limited impact if devices are behind firewalls, have strong network segmentation, and attackers cannot reach the administrative interface.
🎯 Exploit Status
The advisory indicates credential disclosure without authentication requirements, suggesting low complexity exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: CBR40: 2.5.0.10 or later; RBK752/RBR750/RBS750: 3.2.15.25 or later; RBK852/RBR850/RBS850: 3.2.10.11 or later
Vendor Advisory: https://kb.netgear.com/000062351/Security-Advisory-for-Admin-Credential-Disclosure-on-Some-WiFi-Systems-PSV-2020-0043
Restart Required: Yes
Instructions:
1. Log into NETGEAR router admin interface. 2. Navigate to Advanced > Administration > Firmware Update. 3. Check for updates and install latest firmware. 4. Reboot device after update completes.
🔧 Temporary Workarounds
Restrict administrative interface access
allLimit access to router administrative interface to trusted IP addresses only
Change administrative credentials
allChange default or current administrative passwords to strong, unique credentials
🧯 If You Can't Patch
- Isolate affected devices in separate network segments with strict firewall rules
- Disable remote administrative access and only allow local network administration
🔍 How to Verify
Check if Vulnerable:
Access router admin interface, navigate to Advanced > Administration > Firmware Update, check current firmware version against affected versions list.Check Version:
Check via web interface at Advanced > Administration > Firmware Update or via router login pageVerify 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 login attempts followed by successful administrative access
- Unusual administrative configuration changes
- Access from unexpected IP addresses to administrative interface
Network Indicators:
- Unusual traffic patterns from router administrative ports
- Administrative interface access from unauthorized networks
SIEM Query:
source="router_logs" AND (event_type="admin_login" OR event_type="config_change") AND src_ip NOT IN [trusted_admin_ips]