CVE-2026-24436
📋 TL;DR
This vulnerability allows attackers to perform unlimited brute-force attacks against administrative credentials on Tenda W30E V2 routers. Attackers can guess passwords without restriction due to missing rate limiting and account lockout mechanisms. All users running affected firmware versions are vulnerable.
💻 Affected Systems
- Shenzhen Tenda W30E V2 router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of router administrative access leading to network takeover, traffic interception, malware deployment, and lateral movement into connected devices.
Likely Case
Unauthorized administrative access to router allowing configuration changes, DNS hijacking, and network monitoring.
If Mitigated
Limited to failed login attempts with no successful compromise due to strong passwords and network segmentation.
🎯 Exploit Status
Exploitation requires only standard HTTP requests to authentication endpoints with password guessing tools.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates
2. Download latest firmware for W30E V2
3. Access router admin interface
4. Navigate to firmware upgrade section
5. Upload and install new firmware
6. Reboot router
🔧 Temporary Workarounds
Network Access Control
linuxRestrict access to router admin interface to trusted IP addresses only
iptables -A INPUT -p tcp --dport 80 -s TRUSTED_IP -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s TRUSTED_IP -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
Strong Password Enforcement
allImplement complex administrative passwords to increase brute-force resistance
🧯 If You Can't Patch
- Replace vulnerable router with a different model that has proper security controls
- Implement network segmentation to isolate router management interface from general network traffic
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router admin interface under System Status or About sectionCheck Version:
curl -s http://router-ip/status.cgi | grep versionVerify Fix Applied:
Verify firmware version is newer than V16.01.0.19(5037) and test authentication endpoint with rapid login attempts📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts from single IP
- Rapid authentication requests (more than 5 per minute)
- Successful admin login from unusual IP
Network Indicators:
- High volume of HTTP POST requests to /login.cgi or similar endpoints
- Traffic patterns showing password spraying behavior
SIEM Query:
source="router.log" ("login failed" OR "authentication failure") count by src_ip > 10