nvd-mcp

An MCP server that brings NIST National Vulnerability Database (NVD) intelligence directly into Claude. Look up CVEs, search by product, and triage a list of vulnerabilities into a prioritized risk report — all from a natural-language prompt.

Built with FastMCP and the NVD REST API v2 (no API key required).

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Tools

Tool	Description	Key inputs
lookup_cve	Full details for a single CVE	cve_id — e.g. "CVE-2021-44228"
search_cves	CVEs by product or keyword, sorted by CVSS score	keyword, max_results (1–20, default 10)
summarize_risk	Severity breakdown + weighted risk score for a set of CVEs	cve_ids — list of 1–10 CVE IDs

summarize_risk computes a composite risk score using the formula:

score = (CRITICAL×10 + HIGH×5 + MEDIUM×2 + LOW×1) / total_found

Score range: 0 (no risk) → 10 (all CRITICAL).

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Quickstart

1. Clone and install

git clone <repo-url> nvd-mcp
cd nvd-mcp
uv venv --python 3.13
uv pip install -e .

2. Verify the entry point

.venv/bin/nvd-mcp

You should see FastMCP start and wait on stdin — that confirms the server is working. Press Ctrl-C to exit.

3. Connect to Claude Desktop

Open (or create) ~/Library/Application Support/Claude/claude_desktop_config.json and add the nvd-mcp entry:

{
  "mcpServers": {
    "nvd-mcp": {
      "command": "/absolute/path/to/nvd-mcp/.venv/bin/nvd-mcp"
    }
  }
}

Replace /absolute/path/to/nvd-mcp with the actual path on your machine (run pwd inside the project directory to get it).

Restart Claude Desktop. You should see nvd-mcp appear in the tools list.

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Example prompts

Look up CVE-2021-44228 and tell me how severe it is.

Find the 10 most critical CVEs affecting OpenSSL.

Summarize the risk for CVE-2021-44228, CVE-2022-22965, and CVE-2023-38545.
Give me a recommended remediation priority.

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Project layout

src/nvd_mcp/
├── server.py   # FastMCP app — tool definitions and entry point
├── client.py   # Async NVD API v2 HTTP client with retry/backoff
└── models.py   # Pydantic v2 models: NVD response parsing + tool output types

Rate limiting

The NVD public API allows 5 requests per 30 seconds without an API key. summarize_risk staggers its requests automatically. If you need higher throughput, register for a free NVD API key and set the NVD_API_KEY environment variable (the server will pick it up via the Authorization header — see client.py).

Note: NVD_API_KEY support is a one-line addition to the NvdClient headers dict; it is not wired up in this demo to keep the setup keyless.

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Development

# Type check
PYTHONPATH=src .venv/bin/pyright

# Run tests
PYTHONPATH=src .venv/bin/pytest