Vulners MCP Server

Vulners MCP is a Model Context Protocol (MCP) server that provides seamless access to the Vulners vulnerability database through AI assistants like Claude Desktop. It enables security researchers and developers to query comprehensive vulnerability data, search for CVEs, analyze security bulletins, and audit software packages directly through natural language conversations.

Features

• AI Assistant Integration: Works natively with Claude Desktop and other MCP-compatible clients
• Dual Transport Support: Automatically detects and supports both stdio (for Claude Desktop) and HTTP transports
• Comprehensive Tools: 7 MCP tools for vulnerability research including:
  • Full-text Lucene search across 4M+ vulnerability bulletins
  • CVE and bulletin information retrieval
  • Software/package vulnerability auditing
  • CPE search and autocomplete
  • Linux package vulnerability auditing
• Flexible Deployment: prebuilt Docker image (ghcr.io/vulnerscom/vulners-mcp), PyPI package, or local build
• Environment-based Configuration: Simple setup via environment variables

Table of Contents

• Requirements
• Obtaining Vulners API Key
• Authentication
• Quick Start with Claude Desktop
• Installation & Deployment
  • PyPI
  • Docker with run script
  • Docker (manual)
  • Build & run locally
• Configuration / Environment Variables
• Usage & Endpoints
• Testing
• Available Tools
• Development & Contributing
• License

Requirements

• Python 3.13+ (for PyPI or a local build)
• Access to the Vulners API (valid API key and network connectivity)
• (For Docker) Docker engine

Obtaining Vulners API Key

Please, register at Vulners website. Go to the personal menu by clicking at your name at the right top corner. Follow "API KEYS" tab. Generate API key with scope "api" and use it with the library.

Authentication

How you provide your API key depends on which transport you run:

Anonymous tier (HTTP only)

initialize and tools/list always work without a key, so an agent can discover what the server offers before it has one. A tools/call sent without an X-Api-Key header behaves according to whether this deployment has an anonymous tier configured:

Example of the guidance error (no key, no anonymous tier configured):

{
  "isError": true,
  "content": [{
    "type": "text",
    "text": "This server does not hold a privileged API key, and no anonymous tier is configured on this deployment. Send your personal Vulners API key in the X-Api-Key HTTP header. Get a key: sign in at https://vulners.com/userinfo (human, in a browser). Details: https://mcp.vulners.com/auth.md (When configured, this server's anonymous tier is itself size- and rate-limited -- your own key always gets full limits.)"
  }]
}

Sending your own X-Api-Key always gets you full, uncapped (at this layer) access -- the anonymous tier exists so an agent can try the server out, or make a light, occasional call, without first obtaining a key.

No env change is required to enable the anonymous tier on a deployment that already sets VULNERS_API_KEY. In HTTP mode, VULNERS_MCP_ANON_API_KEY falls back to VULNERS_API_KEY when unset -- so that same key now also backs the (rate-limited, size-clamped) anonymous tier. To back the anonymous tier with a separate, dedicated key instead -- so it isn't also your own operator key -- set VULNERS_MCP_ANON_API_KEY explicitly; it always takes precedence over the VULNERS_API_KEY fallback when both are set.

Quick Start with Claude Desktop

The easiest way to use Vulners MCP is through Claude Desktop:

1. Pull the Docker Image

docker pull ghcr.io/vulnerscom/vulners-mcp:latest

Images are published for linux/amd64 and linux/arm64, tagged latest and with each release version (e.g. 1.15.0). To build it yourself instead, see Building from Source.

2. Configure Claude Desktop

Add to your Claude Desktop configuration file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json
Linux: ~/.config/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "vulners": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-e",
        "VULNERS_API_KEY=YOUR_API_KEY_HERE",
        "ghcr.io/vulnerscom/vulners-mcp:latest"
      ]
    }
  }
}

Replace YOUR_API_KEY_HERE with your actual Vulners API key.

3. Restart Claude Desktop

After saving the configuration, restart Claude Desktop. The Vulners MCP server will be available through the 🔌 icon.

4. Start Using

You can now ask Claude questions like:

• "Find recent vulnerabilities in Google Chrome"
• "Show me details for CVE-2025-53770"
• "What are recent exploted vulnerabilities in Citrix products"
• "Audit this software: cpe:2.3🅰️google:chrome:138.0.7204.184:::::::*"
• "Audit ubuntu 22.04 packages 'openssl 3.0.2 amd64' and 'curl 7.81.0-1ubuntu1.14 amd64'"

Installation & Deployment

PyPI

# stdio (Claude Desktop and other local MCP clients)
VULNERS_API_KEY="your_api_key" uvx vulners-mcp

# or install it
pip install vulners-mcp
VULNERS_API_KEY="your_api_key" vulners-mcp

For Claude Desktop, use "command": "uvx", "args": ["vulners-mcp"] with VULNERS_API_KEY in "env".

Docker with run script

For easy HTTP mode deployment, use the provided run script:

./run-docker.sh

It runs a locally built vulners-mcp:latest image (see Building from Source). The server will start in HTTP mode at http://0.0.0.0:8000/mcp. No API key is needed to start it — see Authentication: each caller sends their own key as an X-Api-Key header per request.

Docker (manual)

Run the MCP server in HTTP mode (no API key needed to start it):

docker run -d \
  --name vulners-mcp-http \
  -e MCP_TRANSPORT_MODE="http" \
  -e VULNERS_BASE_URL="https://vulners.com" \
  -p 8000:8000 \
  ghcr.io/vulnerscom/vulners-mcp:latest

Callers then send their own key per request, e.g.:

curl -X POST http://localhost:8000/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -H "X-Api-Key: your_api_key" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"get_supported_os","arguments":{}}}'

For Claude Desktop (stdio mode), the -i flag is used instead, and the key is set as an environment variable (see Authentication — stdio has no per-request header to carry one):

docker run -i --rm \
  -e VULNERS_API_KEY="your_api_key" \
  ghcr.io/vulnerscom/vulners-mcp:latest

Build & run locally

git clone https://github.com/vulnersCom/vulners-mcp.git
cd vulners-mcp
poetry install
# Default transport is stdio, which is why a key belongs in the environment
# here -- see Authentication above. Not needed/used if you instead run with
# MCP_TRANSPORT_MODE=http.
export VULNERS_API_KEY="your_api_key"
poetry run python -m vulners_mcp

Configuration / Environment Variables

Metrics (off by default). The Docker image ships both backends; for a PyPI install add the extra: pip install "vulners-mcp[metrics]" (or [prometheus] / [statsd]).

Transport Mode:

• The server automatically detects the transport mode based on how it's run
• Use MCP_TRANSPORT_MODE=http to explicitly force HTTP mode (for standalone HTTP server)
• Claude Desktop uses stdio mode automatically when run with docker run -i

Usage & Endpoints

With Claude Desktop

Simply ask questions in natural language:

• "Search for Apache vulnerabilities"
• "Get information about CVE-2024-1234"
• "Audit software cpe:/a:vendor:product:version"

HTTP Mode

When running in HTTP mode, clients connect to:

http://<FASTMCP_HOST>:<FASTMCP_PORT>/mcp

Default: http://0.0.0.0:8000/mcp

Send your Vulners API key as an X-Api-Key header on every request for full, uncapped limits (see Authentication). initialize and tools/list always work without one; a keyless tools/call either runs on this deployment's anonymous tier (if configured -- reduced limits) or is rejected immediately with a structured guidance error instead of being forwarded upstream (if not).

The server is stateless (MCP_STATELESS_HTTP=true by default): every request is handled independently, with no server-side session continuity required between calls, so it can be deployed behind a load balancer with no sticky routing.

Testing

poetry install --with dev
poetry run ruff check .
poetry run pytest

The suite mocks the Vulners API, so no key or network access is needed.

Available Tools

The server provides 7 MCP tools for vulnerability research:

Search & Discovery

• search_lucene - 🔍 DISCOVERY TOOL FOR UNKNOWN VULNERABILITIES 🔍 Full-text search in Vulners Knowledge Base using Lucene syntax. Use ONLY when you don't have specific IDs or version information. NEVER use for known CVE/bulletin IDs - use bulletin_by_id instead. NEVER use for specific software versions (e.g., 'Chrome 138.0.7204.184') - use audit_software instead. 🚨 CRITICAL: For vendor/product searches, ALWAYS use cnaAffected.vendor and cnaAffected.product fields - the affectedSoftware field does NOT exist.

• bulletin_by_id - 🚨 PRIMARY TOOL FOR KNOWN IDs 🚨 Fetch a bulletin by CVE or Vulners ID. Returns a COMPACT triage-card summary by default -- id, title, CVSS3, EPSS, CVE list, and a compact exploitation/AI signal -- NOT the full record. Pass fields=[...] to widen (e.g. add 'description', 'cvss', 'cvss2', 'affectedSoftware') or references=True for the linked-bulletin graph; requesting everything can be very large. Supports single ID or list of IDs. When list is provided, references are automatically set to False. NEVER use search_lucene for known IDs.

• query_autocomplete - Autocomplete helper for search inputs (vendors, products, CVEs, etc.). Get search suggestions from the Vulners database.

• search_cpe - Find CPE strings by vendor+product (latest schema). Search for Common Platform Enumeration identifiers in the Vulners database.

Vulnerability Auditing

• audit_software - 🔍 VERSION-SPECIFIC SOFTWARE AUDIT 🔍 Audit specific software versions for known vulnerabilities. Use this when you have exact software version information (e.g., Chrome 138.0.7204.184). NEVER use search_lucene for version-specific software audits.

• audit_linux_packages - Linux package audit (RPM/DEB) for a given distro + version. Analyze Linux package vulnerabilities against the Vulners database.

Information & System Support

• get_supported_os - List supported OS identifiers/versions for Linux package audit. Get available operating systems for vulnerability analysis.

Tool Selection Guidelines

🚨 CRITICAL TOOL SELECTION RULES 🚨

WHEN TO USE EACH TOOL

• bulletin_by_id: Use when you have SPECIFIC IDs

  • ✅ "Analyze CVE-2025-7775" → bulletin_by_id
  • ✅ "Look up CTX694938" → bulletin_by_id
  • ✅ "Tell me about CVE-2021-44228" → bulletin_by_id
  • ✅ Any specific CVE, RHSA, MS, CTX, NCSC, THN, etc. ID

• search_lucene: Use ONLY for DISCOVERY when you don't have specific IDs

  • ✅ "Find vulnerabilities in Apache" → search_lucene
  • ✅ "Show me recent CVEs" → search_lucene
  • ✅ "What vulnerabilities exist in Chrome?" → search_lucene
  • ❌ NEVER use for known IDs - use bulletin_by_id instead

• audit_software: Use for VERSION-SPECIFIC software audits

  • ✅ "Audit Chrome 138.0.7204.184" → audit_software
  • ✅ "Check vulnerabilities in Firefox 120.0" → audit_software
  • ✅ Use when you have vendor + product + version information
  • ❌ Don't use for vendor + product only (use search_lucene instead)

EFFICIENCY RULE: One bulletin_by_id call is sufficient for known IDs. Do NOT follow up with search_lucene unless explicitly asked to broaden scope.

Follow-up Workflow for Audit Tools

When using audit tools (audit_software, audit_linux_packages)

• ✅ Run the audit tool to identify vulnerable software and get CVE IDs
• ✅ Extract CVE IDs from the response vulnerabilities array
• ✅ Use bulletin_by_id with the list of CVE IDs for detailed analysis
• ✅ This provides comprehensive vulnerability information including patches, references, and exploitation data
• ✅ Batch processing with bulletin_by_id is more efficient than multiple individual calls

For detailed tool documentation and parameters, use Claude's tool inspection or check the server's tool list.

Development & Contributing

• Open issues or feature requests on GitHub
• Submit pull requests with improvements
• Ensure compatibility with the Vulners API
• Test both stdio (Claude Desktop) and HTTP modes

Building from Source

git clone https://github.com/vulnersCom/vulners-mcp.git
cd vulners-mcp
docker build -t vulners-mcp:latest .

Releases

Every push to main builds and publishes the Docker image to GHCR (latest and <version> tags). When version in pyproject.toml is new, the same workflow also publishes the package to PyPI and server.json to the MCP Registry. Bump the version in pyproject.toml and both places in server.json with every change (tests/test_server_json.py checks they match).

License

MIT

MCP Name: io.github.vulnersCom/vulners-mcp