Tsup is a zero-config TypeScript bundler powered by esbuild, designed for creating modern JavaScript libraries. Version 4.12.2 introduces minimal changes compared to version 4.12.1, but the release includes important metadata and updated documentation links. While the core functionality remains the same, developers benefit from a more complete package manifest and readily available resources for guidance. Both versions share a robust set of features, including fast bundling, automatic externalization of dependencies to reduce bundle size, and support for various output formats like ESM, CJS, and IIFE.
Tsup simplifies the build process through its command-line interface, allowing developers to focus on code rather than configuration. Key dependencies include esbuild for blazing-fast builds, Rollup for advanced transformations and plugin compatibility, and Sucrase for further code transformations. The package offers out-of-the-box support for TypeScript, JSX, and CSS modules, reducing the need for complex build pipelines. Developers can leverage its configuration options via the tsup.config.js file to customize bundling behavior such as splitting chunks, generating declarations and more. The inclusion of peer dependencies like TypeScript ensures compatibility with developers projects. The library prioritize simple usage with great performance for building high-quality TypeScript based libraries. The release of 4.12.2 ensure the newest version of the library is easily discoverable.
All the vulnerabilities related to the version 4.12.2 of the package
tsup DOM Clobbering vulnerability
A DOM Clobbering vulnerability in tsup v8.3.4 allows attackers to execute arbitrary code via a crafted script in the import.meta.url to document.currentScript in cjs_shims.js components
esbuild enables any website to send any requests to the development server and read the response
esbuild allows any websites to send any request to the development server and read the response due to default CORS settings.
esbuild sets Access-Control-Allow-Origin: * header to all requests, including the SSE connection, which allows any websites to send any request to the development server and read the response.
https://github.com/evanw/esbuild/blob/df815ac27b84f8b34374c9182a93c94718f8a630/pkg/api/serve_other.go#L121 https://github.com/evanw/esbuild/blob/df815ac27b84f8b34374c9182a93c94718f8a630/pkg/api/serve_other.go#L363
Attack scenario:
http://malicious.example.com).fetch('http://127.0.0.1:8000/main.js') request by JS in that malicious web page. This request is normally blocked by same-origin policy, but that's not the case for the reasons above.http://127.0.0.1:8000/main.js.In this scenario, I assumed that the attacker knows the URL of the bundle output file name. But the attacker can also get that information by
/index.html: normally you have a script tag here/assets: it's common to have a assets directory when you have JS files and CSS files in a different directory and the directory listing feature tells the attacker the list of files/esbuild SSE endpoint: the SSE endpoint sends the URL path of the changed files when the file is changed (new EventSource('/esbuild').addEventListener('change', e => console.log(e.type, e.data)))The scenario above fetches the compiled content, but if the victim has the source map option enabled, the attacker can also get the non-compiled content by fetching the source map file.
npm inpm run watchfetch('http://127.0.0.1:8000/app.js').then(r => r.text()).then(content => console.log(content)) in a different website's dev tools.Users using the serve feature may get the source code stolen by malicious websites.