lookup_cve

Look up a CVE by ID from NVD. Returns full details including CVSS scores, description, weaknesses, and CISA KEV status. Args: cve_id: CVE identifier (e.g. CVE-2021-44228)

ServerCVE MCP Server
CategoryRead

How to control lookup_cve ↓

WHAT IT DOES

What lookup_cve does on CVE MCP Server

AI agents call lookup_cve to retrieve information from CVE MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

THE RISK

Low Risk

Why lookup_cve needs a policy

This tool performs a read-only lookup operation. It queries an external database (NVD) and returns structured vulnerability information (CVSS scores, descriptions, weaknesses, CISA KEV status). No side effects, no code execution, no data modification, and no destructive operations.

From the tool's definition Tool description states 'Look up a CVE by ID from NVD. Returns full details' — this is a query/retrieval operation that fetches and returns vulnerability metadata from the National Vulnerability Database without modifying, executing, or deleting any data.

Documented attack patterns abuse exactly the kind of access lookup_cve gives an agent:

POLICY

How to control lookup_cve

PolicyLayer is an MCP gateway — it sits between your AI agents and CVE MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for lookup_cve:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "lookup_cve": {}
  }
}

lookup_cve is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register CVE MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

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EXPLORE

Related tools and policies

More CVE MCP Server tools

Read parse_cvss Parse and explain a CVSS vector string (v2, v3.x, or v4.0). Args: vector: CVS Read calculate_risk_score Calculate a composite 0-100 risk score using CVSS, EPSS, KEV, and PoC data. Read check_exploit_availability Search GitHub for public proof-of-concept (PoC) exploit repositories for a CVE. Result Read check_ip_reputation Check an IP address reputation via AbuseIPDB and GreyNoise Community. Returns abuse co Read check_kev Check if a CVE is in the CISA Known Exploited Vulnerabilities (KEV) catalog. Args: Read check_package_vulns Check a package for known vulnerabilities via OSV.dev. Args: package: Package Read check_poc_exists Search for proof-of-concept exploits across GitHub, Exploit-DB, and Nuclei templates. Read check_ransomware_intel Check if a Bitcoin address is associated with a known ransomware family using the Rans

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about lookup_cve

What does the lookup_cve tool do? +

Look up a CVE by ID from NVD. Returns full details including CVSS scores, description, weaknesses, and CISA KEV status. Args: cve_id: CVE identifier (e.g. CVE-2021-44228). It is categorised as a Read tool in the CVE MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on lookup_cve? +

Register the CVE MCP Server MCP server in PolicyLayer and add a rule for lookup_cve: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches CVE MCP Server. Nothing to install.

What risk level is lookup_cve? +

lookup_cve is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit lookup_cve? +

Yes. Add a rate_limit block to the lookup_cve rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block lookup_cve completely? +

Set action: deny in the PolicyLayer policy for lookup_cve. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides lookup_cve? +

lookup_cve is provided by the CVE MCP Server MCP server (mukul975/cve-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every CVE MCP Server tool call.

Start from CVE MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

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27 CVE MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.