CVE-2026-2930
📋 TL;DR
A stack-based buffer overflow vulnerability in Tenda A18 routers allows remote attackers to execute arbitrary code by manipulating the boundary argument in the webCgiGetUploadFile function. This affects Tenda A18 routers running firmware version 15.13.07.13. Attackers can exploit this without authentication to potentially take control of affected devices.
💻 Affected Systems
- Tenda A18
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, lateral movement to internal networks, and persistent backdoor installation.
Likely Case
Device takeover for botnet recruitment, credential theft, or network traffic interception.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound rules and network segmentation.
🎯 Exploit Status
Public exploit code is 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. 3. Upload via router admin interface. 4. Reboot router.
🔧 Temporary Workarounds
Disable Remote Management
allTurn off remote administration features to prevent external exploitation.
Access router admin interface > Advanced Settings > Remote Management > Disable
Network Segmentation
allIsolate router management interface to separate VLAN.
🧯 If You Can't Patch
- Replace affected devices with patched or different models
- Implement strict firewall rules blocking all inbound traffic to router management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface. If version is 15.13.07.13, device is vulnerable.Check Version:
Check via router web interface at 192.168.0.1 or 192.168.1.1Verify Fix Applied:
Verify firmware version has been updated to a version newer than 15.13.07.13.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to /cgi-bin/UploadCfg
- Large boundary parameter values in upload requests
Network Indicators:
- Exploit traffic patterns matching public PoC
- Unexpected connections from router to external IPs
SIEM Query:
source_ip=router_ip AND dest_port=80 AND uri_path="/cgi-bin/UploadCfg" AND http_method="POST"