CVE-2026-27513
📋 TL;DR
This CSRF vulnerability in Tenda F3 router firmware allows attackers to trick authenticated administrators into making unauthorized configuration changes via malicious web requests. Anyone using Tenda F3 routers with the vulnerable firmware version is affected. The attack requires the administrator to be logged into the router's web interface while visiting a malicious website.
💻 Affected Systems
- Shenzhen Tenda F3 Wireless Router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router takeover including changing admin credentials, enabling remote access, redirecting DNS, or disabling security features, potentially leading to network compromise.
Likely Case
Unauthorized configuration changes such as DNS hijacking, firewall rule modifications, or network settings alteration leading to man-in-the-middle attacks.
If Mitigated
No impact if proper CSRF protections are implemented or if administrators don't visit malicious sites while logged into the router interface.
🎯 Exploit Status
CSRF attacks are well-understood and easy to implement. Requires social engineering to get administrator to visit malicious site.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: No
Instructions:
Check Tenda website for firmware updates. If available, download latest firmware and upload via router web interface under System Tools > Firmware Upgrade.
🔧 Temporary Workarounds
Use separate browser for router admin
allUse a dedicated browser or private/incognito window only for router administration and close it when done.
Implement browser CSRF protection
allUse browser extensions that add CSRF protection or disable automatic form submission.
🧯 If You Can't Patch
- Restrict router admin interface to internal network only and disable WAN access
- Implement network segmentation to isolate router management traffic
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface under System Status. If version is V12.01.01.55_multi, you are vulnerable.Check Version:
No CLI command - check via web interface at http://router_ip or via System Status pageVerify Fix Applied:
Verify firmware version has been updated to a version later than V12.01.01.55_multi.📡 Detection & Monitoring
Log Indicators:
- Multiple configuration changes from same IP in short time
- Unexpected admin login/logout events
- Configuration changes without corresponding admin login
Network Indicators:
- HTTP POST requests to router admin interface from external IPs
- Unusual configuration change patterns
SIEM Query:
source="router_logs" AND (event_type="config_change" OR event_type="admin_action") | stats count by src_ip, user | where count > threshold