CVE-2026-57496 — NetLicensing MCP Server is a natural-language interface that enables agentic applications…¶

Key facts

CVE-2026-57496 is a Critical (9.6) vulnerability: NetLicensing MCP Server is a natural-language interface that enables agentic applications…. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-57496
Severity	Critical (9.6)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-57496/

Details¶

English | 한국어

Description¶

NetLicensing MCP Server is a natural-language interface that enables agentic applications to manage the software-licensing lifecycle in Labs64 NetLicensing. Prior to 0.1.8, netlicensing_get_product passes the caller-controlled product_number to src/netlicensing_mcp/tools/products.py, which interpolates it into a REST path consumed by nl_get() in src/netlicensing_mcp/client.py without path-segment validation. A traversal segment can be normalized from the intended product path to the /token endpoint, after which the response is serialized through _wrap_json instead of _wrap_json_token_read, bypassing redact_token_read() protections for APIKEY number and SHOP shopURL fields. An authenticated MCP client with a non-administrative API key can retrieve plaintext token values, and a recovered administrative token can provide broad read, write, and delete access to the NetLicensing account. This issue is fixed in version 0.1.8.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-57496
Type	PATH_TRAVERSAL
CVSS Score	9.6

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-57496/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-2026-57496

# 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/Labs64/NetLicensing-MCP/commit/b8fd0ea76d533202573eb24add9fb2fbd9331496
https://github.com/Labs64/NetLicensing-MCP/pull/6
https://github.com/Labs64/NetLicensing-MCP/releases/tag/0.1.8
https://github.com/Labs64/NetLicensing-MCP/security/advisories/GHSA-hxpf-9xvq-wph8

Generated by PoC Generator on 2026-10-16T06:17:35.447695371

Frequently asked questions¶

What is CVE-2026-57496?¶

CVE-2026-57496 is a Critical (9.6) vulnerability: NetLicensing MCP Server is a natural-language interface that enables agentic applications…. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-57496?¶

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-2026-57496?¶

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.