CVE-2025-9089
📋 TL;DR
A stack-based buffer overflow vulnerability in Tenda AC20 routers allows remote attackers to execute arbitrary code by sending specially crafted requests to the SetIpMacBind function. This affects Tenda AC20 routers running firmware version 16.03.08.12. Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- Tenda AC20
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, allowing attackers to install persistent malware, pivot to internal networks, or create botnet nodes.
Likely Case
Remote code execution enabling attackers to modify router settings, intercept network traffic, or use the device as a foothold for further attacks.
If Mitigated
Denial of service or limited impact if exploit attempts are blocked by network controls, though the vulnerability remains present.
🎯 Exploit Status
Public Python exploit script available, making exploitation straightforward for attackers with basic skills.
🛠️ 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. Download the latest firmware for AC20. 3. Access router admin interface. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install the new firmware. 6. Reboot the router.
🔧 Temporary Workarounds
Block External Access to Router Admin
linuxPrevent external access to the router's web interface to block remote exploitation attempts.
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
Disable Remote Management
allTurn off remote management features in the router settings to limit attack surface.
🧯 If You Can't Patch
- Isolate affected routers in a separate VLAN with strict firewall rules.
- Implement network monitoring to detect exploitation attempts and block malicious IPs.
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via admin interface at System Status > Firmware Version.Check Version:
curl -s http://router-ip/ | grep -i firmwareVerify Fix Applied:
Verify firmware version has been updated to a version newer than 16.03.08.12.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/SetIpMacBind
- Multiple failed exploit attempts in router logs
- Unexpected router reboots or configuration changes
Network Indicators:
- HTTP requests with unusually long parameters to router IP
- Traffic patterns suggesting buffer overflow attempts
SIEM Query:
source="router_logs" AND (uri="/goform/SetIpMacBind" OR message="buffer overflow")🔗 References
- https://github.com/ZZ2266/.github.io/blob/main/AC20/fromSetIpMacBind/readme.md
- https://github.com/ZZ2266/.github.io/blob/main/AC20/fromSetIpMacBind/readme.md#poc-python-exploit-script
- https://vuldb.com/?ctiid.320357
- https://vuldb.com/?id.320357
- https://vuldb.com/?submit.632039
- https://www.tenda.com.cn/
