fetch-cwe-list

A simple, secure Node.js module that fetches and parses the latest Common Weakness Enumeration (CWE) list from MITRE.

Quick Start

npm install fetch-cwe-list

const fetchCweList = require('fetch-cwe-list')

// Fetch latest CWE list
const cweList = await fetchCweList()
console.log(`Fetched ${cweList.length} CWE entries`)

// Fetch specific version
const cweListV413 = await fetchCweList('4.13')

That's it. Each entry includes parsed CWE data with enriched external references.

Features

• Live data — Always current, fetched directly from MITRE
• Enriched — CAPEC mappings, CVE context, hierarchy relationships, external references
• Cached — Optional 1-hour TTL cache (configurable)
• Query helpers — findById, findByName, findByCapec for common lookups
• Secure — 30s timeout, 100MB size limit, XXE protection, no shared state
• TypeScript — Full type definitions included

Usage

Fetch and iterate

const cweList = await fetchCweList()
cweList.forEach(cwe => {
  console.log(`${cwe.ID}: ${cwe.Name}`)
})

Use query helpers

const { findById, findByName, findByCapec } = require('fetch-cwe-list')
const cweList = await fetchCweList()

const cwe79      = findById(cweList, '79')
const injections = findByName(cweList, 'injection')
const xssCwes    = findByCapec(cweList, '209')  // CAPEC-209: XSS Using MIME Type Mismatch

Access enriched data

const cweList = await fetchCweList()
const cwe79 = findById(cweList, '79')

// CAPEC attack patterns
console.log(cwe79.CAPEC_IDs)  // ['63', '85', '209', '588', '591', '592']

// Hierarchy (parent weaknesses)
console.log(cwe79.Hierarchy.parents)  // ['74']

// Known CVEs
cwe79.Known_CVEs.forEach(({ id, description }) => {
  console.log(`${id}: ${description}`)
})

Cache control

const { clearCache } = require('fetch-cwe-list')

const list1 = await fetchCweList()  // Downloads, caches for 1 hour
const list2 = await fetchCweList()  // Instant (cached)

// Bypass cache
const fresh = await fetchCweList('latest', { cache: false })

// Invalidate cache
clearCache()

API Reference

fetchCweList([version], [opts])

Parameters:

• version (string, optional) — CWE version to fetch (e.g., '4.13'). Defaults to 'latest'.
• opts (object, optional) — Options:
  • cache (boolean, optional) — Set to false to bypass cache. Default: true

Returns:

• Promise resolving to array of CWE objects

Throws:

• Error if download fails, timeout occurs, or version not found

clearCache()

Clears the in-memory cache. The cache instance itself is not exposed to prevent external poisoning via cache.set().

findById(cweList, id)

Find a single CWE by its ID string.

Parameters:

• cweList — Array returned by fetchCweList()
• id (string) — The CWE ID, e.g., '79'

Returns:

• CWE object or undefined

findByName(cweList, pattern)

Find all CWEs whose name contains the given string (case-insensitive).

Parameters:

• cweList — Array returned by fetchCweList()
• pattern (string) — Case-insensitive substring

Returns:

• Array of CWE objects

Note: RegExp is intentionally not supported to prevent ReDoS attacks.

findByCapec(cweList, capecId)

Find all CWEs that map to a given CAPEC ID string.

Parameters:

• cweList — Array returned by fetchCweList()
• capecId (string) — The CAPEC ID, e.g., '86'

Returns:

• Array of CWE objects

Data Structure

Each CWE entry contains MITRE's fields plus enriched data after v0.1.0:

| Field | Type | Always present | Description | |-------|------|---------------|-------------| | ID | string | Yes | CWE ID (normalized from numeric parser output) | | CAPEC_IDs | string[] | Yes | Mapped CAPEC attack pattern IDs (empty array if none) | | Known_CVEs | { id, description }[] | Yes | CVEs from Observed_Examples (empty array if none) | | Hierarchy | object | No | Parent relationships (absent if no Related_Weaknesses) | | References.Full_Details | object[] | No | Enriched external reference objects |

Example entry:

{
  ID: "79",
  Name: "Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')",
  Status: "Stable",
  Description: "...",
  CAPEC_IDs: ['63', '85', '209', '588', '591', '592'],
  Known_CVEs: [
    { id: 'CVE-2021-1879', description: '...' }
  ],
  Hierarchy: {
    parents: ['74'],
    relationships: [
      { nature: 'ChildOf', cweId: '74', viewId: '1000', ordinal: 'Primary' }
    ]
  },
  References: {
    Reference: [{ External_Reference_ID: "REF-2" }],
    Full_Details: [
      {
        Reference_ID: "REF-2",
        Author: "OWASP",
        Title: "Cross Site Scripting (XSS)",
        URL: "https://www.owasp.org/..."
      }
    ]
  }
}

Note: Single references are automatically normalized to arrays and enriched just like multiple references. IDs are normalized to strings for consistency across all API surfaces.

MCP Server

Experimental: Alpha release. APIs may change.

An MCP server is available for using this library as tools in LLM agents like Claude Code, Codex, etc.:

npx fetch-cwe-list-mcp

See packages/fetch-cwe-list-mcp for full setup and usage.

License

MIT

Author

Alejandro Saenz