CVE-2025-9605
📋 TL;DR
A stack-based buffer overflow vulnerability in Tenda AC21 and AC23 routers allows remote attackers to execute arbitrary code by sending specially crafted requests to the GetParentControlInfo function. This affects devices running firmware version 16.03.08.16. The vulnerability is remotely exploitable without authentication.
💻 Affected Systems
- Tenda AC21
- Tenda AC23
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to persistent backdoor installation, network traffic interception, lateral movement to connected devices, and participation in botnets.
Likely Case
Router takeover enabling DNS hijacking, credential theft from network traffic, and denial of service to connected devices.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering, though internal network compromise remains possible.
🎯 Exploit Status
Public exploit code is available in GitHub repositories. The vulnerability requires sending a crafted HTTP request to the vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check Tenda's official website for firmware updates. 2. If available, download the latest firmware for your specific model. 3. Access router admin interface. 4. Navigate to firmware upgrade section. 5. Upload and apply the new firmware. 6. Reboot the router.
🔧 Temporary Workarounds
Network Segmentation
allIsolate affected routers in a separate network segment with strict firewall rules.
Access Control
linuxBlock external access to router management interface using firewall rules.
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Replace affected routers with different models that are not vulnerable
- Implement strict network monitoring and intrusion detection for suspicious traffic to router management interfaces
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via admin interface. If version is 16.03.08.16, the device is vulnerable.Check Version:
curl -s http://router-ip/goform/GetParentControlInfo | grep -i version or check web admin interfaceVerify Fix Applied:
After updating firmware, verify the version number has changed from 16.03.08.16.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to /goform/GetParentControlInfo
- Multiple failed buffer overflow attempts in system logs
- Unexpected router reboots or crashes
Network Indicators:
- HTTP traffic to router IP on port 80/443 with malformed mac parameter
- Unusual outbound connections from router to unknown IPs
SIEM Query:
source="router_logs" AND (url="/goform/GetParentControlInfo" OR message="buffer overflow")🔗 References
- https://github.com/XXRicardo/iot-cve/blob/main/Tenda/AC21/AC21V1.0re_V16.03.08.16.md
- https://github.com/XXRicardo/iot-cve/blob/main/Tenda/AC23/Stack-Based%20Buffer%20Overflow%20in%20Tenda%20Wi-Fi%205%20Router%20AC23%EF%BC%88AC23V1.0re_V16.03.07.52%EF%BC%89.md
- https://vuldb.com/?ctiid.321783
- https://vuldb.com/?id.321783
- https://vuldb.com/?submit.636545
- https://vuldb.com/?submit.636548
- https://www.tenda.com.cn/
- https://github.com/XXRicardo/iot-cve/blob/main/Tenda/AC21/AC21V1.0re_V16.03.08.16.md
- https://github.com/XXRicardo/iot-cve/blob/main/Tenda/AC23/Stack-Based%20Buffer%20Overflow%20in%20Tenda%20Wi-Fi%205%20Router%20AC23%EF%BC%88AC23V1.0re_V16.03.07.52%EF%BC%89.md
