tsup is a modern bundler that leverages esbuild for incredibly fast builds, streamlining the development process for TypeScript projects. Comparing versions 4.3.1 and 4.3.0, while the core functionality remains consistent, a few subtle changes warrant attention. Both share the same set of dependencies, including crucial tools like Rollup, esbuild, Sucrase, and PostCSS, indicating a stable and feature-rich environment for building JavaScript libraries and applications. The primary difference lies in the dist metadata, specifically the unpackedSize. Version 4.3.1 has a slightly larger unpacked size (642131 bytes) than 4.3.0 (641878 bytes). While seemingly minor, this suggests potential improvements or adjustments in the bundled output, possibly related to code optimization, added comments, or minor bug fixes. The newer release date of 4.3.1 also indicates a very recent patch, hinting at possible bug fixes or small improvements. For developers, tsup offers a zero-config experience to bundle Typescript code. If are already using tsup consider moving to the latest version, since the changes are related to improvements, and no breaking changes are present. Always check the library release notes for more information.
All the vulnerabilities related to the version 4.3.1 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.