CVE-2026-18686 — A vulnerability was detected in GL.iNet GL-MT3000 up to 4.4.5.¶
Key facts
CVE-2026-18686 is a Critical (9.8) vulnerability: A vulnerability was detected in GL.iNet GL-MT3000 up to 4.4.5.. This entry ships a detection-only PoC and a Docker test lab.
| CVE | CVE-2026-18686 |
| Severity | Critical (9.8) |
| Detection / prevention | — |
| PoC | poc.py |
| Source | 2026/CVE-2026-18686/ |
Details¶
English | 한국어
Description¶
A vulnerability was detected in GL.iNet GL-MT3000 up to 4.4.5. The affected element is the function nas-web.add_user of the file /cgi-bin/glc of the component nas-web RPC Wrapper. Performing a manipulation results in command injection. The attack can be initiated remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure and confirmed the existence of the vulnerability.
Vulnerability Details¶
| Property | Value |
|---|---|
| CVE ID | CVE-2026-18686 |
| Type | COMMAND_INJECTION |
| CVSS Score | 9.8 |
Proof of Concept¶
Download¶
# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-18686/poc.py
Usage¶
# Run PoC against target
python3 poc.py --target <TARGET_URL>
# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>
⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.
Test Lab¶
This repository includes a Docker-based test environment with both vulnerable and patched applications.
Quick Start¶
# Clone and navigate to CVE directory
cd CVE-2026-18686
# Start both applications
docker-compose up -d
# Run tests
./run-tests.sh # Linux/Mac
./run-tests.ps1 # Windows PowerShell
Application Endpoints¶
| Application | URL | Status |
|---|---|---|
| Vulnerable App | http://localhost:8080 | Shows vulnerability |
| Patched App | http://localhost:8081 | Demonstrates fix |
Directory Structure¶
├── README.md # English documentation
├── README_KO.md # Korean documentation
├── poc.py # PoC detection script
├── docker-compose.yml # Container orchestration
├── run-tests.sh # Linux/Mac test runner
├── run-tests.ps1 # Windows test runner
├── vulnerable-app/ # Vulnerable version
│ ├── app.py
│ ├── Dockerfile
│ └── requirements.txt
└── patched-app/ # Fixed version
├── app.py
├── Dockerfile
└── requirements.txt
References¶
- https://github.com/coconut652-7/IOT_Vul_Public/tree/main/Glinet/MT3000/nas-web/ADD_USER_ADD_SHARE
- https://vuldb.com/cve/CVE-2026-18686
- https://vuldb.com/submit/856139
- https://vuldb.com/vuln/385612
- https://vuldb.com/vuln/385612/cti
Generated by PoC Generator on 2026-08-04T10:09:04.803343
Frequently asked questions¶
What is CVE-2026-18686?¶
CVE-2026-18686 is a Critical (9.8) vulnerability: A vulnerability was detected in GL.iNet GL-MT3000 up to 4.4.5.. This entry ships a detection-only PoC and a Docker test lab.
How do I detect CVE-2026-18686?¶
Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.
How do I block or mitigate CVE-2026-18686?¶
Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.
For authorized security testing and research only. See the full source and NVD record.