CVE-2025-5849
📋 TL;DR
A critical stack-based buffer overflow vulnerability in Tenda AC15 routers allows remote attackers to execute arbitrary code by sending specially crafted HTTP POST requests to the /goform/SetRemoteWebCfg endpoint. This affects Tenda AC15 routers running firmware version 15.03.05.19_multi. Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- Tenda AC15
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, lateral movement to internal networks, persistent backdoor installation, and data exfiltration.
Likely Case
Router takeover allowing traffic interception, DNS hijacking, credential theft, and use as botnet node.
If Mitigated
Limited impact if device is behind firewall with restricted WAN access, though internal threats remain possible.
🎯 Exploit Status
Public exploit details are available, making exploitation straightforward for attackers with basic skills.
🛠️ 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 AC15. 3. Access router admin interface. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to the vulnerable endpoint by disabling remote management features.
Network Segmentation
allIsolate AC15 routers in separate VLAN with strict firewall rules blocking unnecessary HTTP traffic.
🧯 If You Can't Patch
- Replace affected routers with different models or brands that are not vulnerable
- Implement strict network access controls to limit traffic to router management interfaces
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status or System Tools. If version is exactly 15.03.05.19_multi, device is vulnerable.Check Version:
No CLI command available. Must check via web interface at http://router_ip or via admin panel.Verify Fix Applied:
After updating firmware, verify version has changed from 15.03.05.19_multi to a newer version.📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /goform/SetRemoteWebCfg with unusual remoteIp parameter values
- Router crash or reboot logs
- Unusual outbound connections from router
Network Indicators:
- HTTP traffic to router on port 80/443 with POST to vulnerable endpoint
- Unusual payload sizes in HTTP requests to router
SIEM Query:
source="router_logs" AND (url="/goform/SetRemoteWebCfg" OR url="*SetRemoteWebCfg*") AND method="POST"