CVE-2026-2191
📋 TL;DR
A stack-based buffer overflow vulnerability exists in Tenda AC9 routers running firmware version 15.03.06.42_multi. Remote attackers can exploit this by manipulating the security.ddos.map argument in the formGetDdosDefenceList function to execute arbitrary code. This affects users of vulnerable Tenda AC9 routers exposed to network access.
💻 Affected Systems
- Tenda AC9
⚠️ 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
Remote code execution leading to complete device compromise, persistence installation, network pivoting, and data exfiltration.
Likely Case
Device crash/reboot causing service disruption, or limited code execution for network reconnaissance.
If Mitigated
Denial of service from failed exploitation attempts if proper network segmentation exists.
🎯 Exploit Status
Public exploit code is available in GitHub repositories, making exploitation straightforward for attackers.
🛠️ 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 for AC9
3. Access router admin interface
4. Navigate to firmware upgrade section
5. Upload and apply new firmware
6. Wait for router to reboot
🔧 Temporary Workarounds
Network Segmentation
allIsolate Tenda AC9 routers from untrusted networks and limit access to management interfaces.
Disable Remote Management
allTurn off WAN-side management access to prevent external exploitation.
🧯 If You Can't Patch
- Replace vulnerable devices with patched or different model routers
- Implement strict firewall rules to block all traffic to router management interfaces from untrusted networks
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status or Firmware Upgrade section.Check Version:
Login to router web interface and navigate to System Status pageVerify Fix Applied:
Verify firmware version has changed from 15.03.06.42_multi to a newer version.📡 Detection & Monitoring
Log Indicators:
- Multiple failed connection attempts to router management interface
- Unusual POST requests to formGetDdosDefenceList endpoint
- Router reboot logs without user action
Network Indicators:
- Unusual traffic patterns to router management port (typically 80/443)
- Exploit payload patterns in network traffic
SIEM Query:
source_ip="router_ip" AND (uri_path="*formGetDdosDefenceList*" OR event_type="device_reboot")