CVE-2026-2148
📋 TL;DR
This vulnerability in Tenda AC21 routers allows remote attackers to access sensitive information through the web management interface. Attackers can exploit the /cgi-bin/DownloadFlash file to disclose system information without authentication. Organizations using Tenda AC21 routers with the affected firmware are at risk.
💻 Affected Systems
- Tenda AC21
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Attackers obtain router configuration details, credentials, or network topology information that could enable further attacks.
Likely Case
Information disclosure revealing system details that could aid in reconnaissance for more sophisticated attacks.
If Mitigated
Limited impact if routers are behind firewalls with restricted web interface access.
🎯 Exploit Status
Public exploit available on GitHub, requires only HTTP access to the router's web interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.tenda.com.cn/
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates
2. Download latest firmware
3. Access router admin panel
4. Upload and apply firmware update
5. Reboot router
🔧 Temporary Workarounds
Disable Web Management Interface
allPrevent external access to the vulnerable web interface
Access router admin panel > Advanced Settings > Remote Management > Disable
Restrict Web Interface Access
allLimit web interface access to trusted IP addresses only
Access router admin panel > Advanced Settings > Firewall > Add IP restriction rules
🧯 If You Can't Patch
- Place router behind firewall with strict inbound rules blocking port 80/443
- Disable remote management and only allow local network access to web interface
🔍 How to Verify
Check if Vulnerable:
Attempt to access http://[router-ip]/cgi-bin/DownloadFlash and check if it returns sensitive informationCheck Version:
Access router admin panel > System Status to check firmware versionVerify Fix Applied:
After applying workarounds, verify the DownloadFlash endpoint is no longer accessible or returns error📡 Detection & Monitoring
Log Indicators:
- HTTP GET requests to /cgi-bin/DownloadFlash
- Unusual access to router web interface
Network Indicators:
- External IPs accessing router web management port
- Multiple failed then successful access to DownloadFlash endpoint
SIEM Query:
source="router-logs" AND (uri="/cgi-bin/DownloadFlash" OR user_agent="curl" OR user_agent="wget")