VulnMCP

VulnMCP is an MCP server built with FastMCP that provides AI clients, chat agents, and other automated systems with tools for vulnerability management. It offers modular "skills" that can be easily extended or integrated, enabling intelligent analysis and automated insights on software vulnerabilities.

Features

• Vulnerability Severity Classification -- Automatically assess the criticality of vulnerabilities using CIRCL's fine-tuned NLP models: CIRCL/vulnerability-severity-classification-roberta-base (English), CIRCL/vulnerability-severity-classification-chinese-macbert-base (Chinese), and CIRCL/vulnerability-severity-classification-russian-ruRoberta-large (Russian).
• CWE Classification -- Predict CWE categories from vulnerability descriptions using CIRCL/cwe-parent-vulnerability-classification-roberta-base.
• Vulnerability Lookup -- Query the Vulnerability Lookup API to get detailed information about specific CVEs, search vulnerabilities by source, CWE, product, or date, find community comments, and discover curated vulnerability bundles.
• KEV Catalog -- Browse and filter Known Exploited Vulnerability (KEV) entries, check whether a CVE appears in a KEV catalog, find recently added entries, and filter by catalog origin (CISA KEV, CIRCL, EUVD KEV).
• GCVE Registry -- Query the GCVE Global Numbering Authority (GNA) registry and references to discover vulnerability allocators and KEV catalog identifiers.
• Modular Architecture -- Easily add new skills or tools to expand the functionality of the MCP server.

Installation

Requires Python 3.10+ and Poetry v2+.

git clone https://github.com/vulnerability-lookup/VulnMCP.git
cd VulnMCP
poetry install

Running the MCP server

stdio (default)

The default transport, used by most MCP clients (Claude Code, Claude Desktop, etc.):

poetry run vulnmcp

HTTP transport

For network access or multiple concurrent clients:

poetry run fastmcp run vulnmcp/server.py --transport http --host 127.0.0.1 --port 9000

Available tools

Tool	Description
classify_severity	Classify vulnerability severity (low/medium/high/critical) from a text description. Supports English, Chinese, and Russian with auto-detection.
classify_cwe	Predict CWE categories from a vulnerability description. Returns top-5 predictions with parent CWE mapping.
get_recent_vulnerabilities_by_cwe	Fetch the 3 most recent CVEs for a given CWE ID.
get_vulnerability	Look up a specific vulnerability by ID (e.g. CVE-2025-14847) with optional comments, sightings, bundles, linked vulnerabilities, and KEV enrichment.
search_vulnerabilities	Search vulnerabilities with filters: source, CWE, product, date range, pagination, and optional KEV-aware prioritization.
search_sightings	Search vulnerability sightings (seen/exploited/patched/etc.) with filters to identify what is actively discussed or abused.
create_sighting	Create a new sighting for a vulnerability (requires API permissions on most instances).
get_most_sighted_vulnerabilities	Retrieve a ranking of vulnerabilities by sighting activity to help prioritize important issues.
search_comments	Search community comments related to vulnerabilities, with filters by vulnerability ID or author.
search_bundles	Search curated vulnerability bundles (grouped CVEs for a campaign, product, or incident), with filters by vulnerability ID or author.
list_kev_entries	List and filter KEV catalog entries by vulnerability ID, status reason, exploited flag, date range, author, or origin catalog UUID.
guess_cpes	Query cpe-guesser with product keywords to infer likely CPE identifiers.
list_gna_entries	List all Global Numbering Authorities (GNA) from the GCVE registry.
get_gna_entry	Get a specific GNA entry by numeric ID or exact short name.
search_gna	Search GNA entries by name (case-insensitive substring match).
list_gcve_references	List GCVE references including KEV catalog UUIDs for use with list_kev_entries.

List all tools:

poetry run fastmcp list vulnmcp/server.py

Testing tools from the command line

Use fastmcp call to invoke any tool directly:

# Look up a specific CVE
poetry run fastmcp call vulnmcp/server.py get_vulnerability vulnerability_id=CVE-2025-14847

# Search for recent SQL injection vulnerabilities
poetry run fastmcp call vulnmcp/server.py search_vulnerabilities cwe=CWE-89 per_page=5

# Retrieve top most-sighted vulnerabilities
poetry run fastmcp call vulnmcp/server.py get_most_sighted_vulnerabilities limit=5

# Search comments for a specific CVE
poetry run fastmcp call vulnmcp/server.py search_comments vuln_id=CVE-2024-3094

# Search bundles related to a CVE
poetry run fastmcp call vulnmcp/server.py search_bundles vuln_id=CVE-2024-3094

# Check if a CVE is in a KEV catalog
poetry run fastmcp call vulnmcp/server.py list_kev_entries vuln_id=CVE-2021-44228

# List recent KEV entries from the last week
poetry run fastmcp call vulnmcp/server.py list_kev_entries date_from=2026-03-18 per_page=5

# List KEV entries from the CISA KEV catalog only
poetry run fastmcp call vulnmcp/server.py list_kev_entries vulnerability_lookup_origin=405284c2-e461-4670-8979-7fd2c9755a60 per_page=5

# Guess likely CPE values from product keywords
poetry run fastmcp call vulnmcp/server.py guess_cpes query='["outlook","connector"]'

# List all GNA entries from the GCVE registry
poetry run fastmcp call vulnmcp/server.py list_gna_entries

# Look up a specific GNA by short name
poetry run fastmcp call vulnmcp/server.py get_gna_entry short_name=CIRCL

# Search GNA entries
poetry run fastmcp call vulnmcp/server.py search_gna query=cert

# List GCVE references (includes KEV catalog UUIDs)
poetry run fastmcp call vulnmcp/server.py list_gcve_references

# Classify severity from a description
poetry run fastmcp call vulnmcp/server.py classify_severity \
    description="A remote code execution vulnerability allows an attacker to execute arbitrary code via a crafted JNDI lookup."

# Classify CWE from a description
poetry run fastmcp call vulnmcp/server.py classify_cwe \
    description="Fix buffer overflow in authentication handler"

Connecting to Claude Code

Register VulnMCP as an MCP server in Claude Code with:

claude mcp add vulnmcp -- poetry --directory /path/to/VulnMCP run vulnmcp

Or with fastmcp install:

poetry run fastmcp install claude-code vulnmcp/server.py --name VulnMCP

Once registered, the tools are available to Claude Code. You can verify with:

claude mcp list

Configuration

Environment variable	Description	Default
VULNMCP_LOOKUP_URL	Base URL for the Vulnerability Lookup API	https://vulnerability.circl.lu
VULNMCP_CPE_GUESSER_URL	Base URL for the cpe-guesser API	https://cpe-guesser.cve-search.org
VULNMCP_API_KEY	API key used for authenticated actions such as creating sightings	(unset)

Contributing

Please read CONTRIBUTING.md before opening a pull request.

Note: this repository currently runs an experiment where only computer-assisted (AI-related) contributions are accepted.

License

AGPL-3.0-or-later