CVE-2025-11356
📋 TL;DR
A buffer overflow vulnerability in Tenda AC23 routers allows remote attackers to execute arbitrary code by exploiting improper input validation in the sscanf function. This affects Tenda AC23 routers running firmware versions up to 16.03.07.52. Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- Tenda AC23
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, creation of persistent backdoors, lateral movement into internal networks, and botnet recruitment.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept traffic, or use the device as a pivot point for further attacks.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering and network segmentation.
🎯 Exploit Status
Public exploit code exists in GitHub repositories. The vulnerability requires no authentication and has straightforward exploitation.
🛠️ 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 AC23 model. 3. Log into router admin interface. 4. Navigate to firmware upgrade section. 5. Upload and apply new firmware. 6. Reboot router after update completes.
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to router administration interface
Network segmentation
allIsolate router management interface to separate VLAN
🧯 If You Can't Patch
- Implement strict firewall rules blocking all inbound traffic to router management interface
- Replace vulnerable devices with patched or alternative router models
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface. If version is 16.03.07.52 or lower, device is vulnerable.Check Version:
Login to router web interface and check System Status or Firmware Upgrade sectionVerify Fix Applied:
Verify firmware version is higher than 16.03.07.52 after update.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/SetStaticRouteCfg
- Multiple failed buffer overflow attempts
- Unexpected router reboots or configuration changes
Network Indicators:
- Exploit traffic patterns to router management interface
- Unusual outbound connections from router
SIEM Query:
source="router_logs" AND (uri="/goform/SetStaticRouteCfg" OR message="buffer overflow")