Tsup is a zero-config TypeScript bundler powered by esbuild, designed for creating modern JavaScript libraries and applications with speed and ease. Comparing versions 4.3.0 and 4.2.0 reveals some subtle but important changes impacting developers. The core dependencies remain largely consistent, suggesting a focus on incremental improvements rather than a major overhaul. Both versions rely on essential tools like esbuild for blazing-fast builds, rollup for flexible bundling, and sucrase for faster TypeScript parsing.
The critical difference lies in the updated tsup version listed as a devDependency. Version 4.3.0 depends on "^4.2.0" while version 4.2.0 depends on "^4.1.0." This suggests that 4.3.0 includes internal updates or bug fixes within the tsup package itself, potentially improving performance, stability, or compatibility. Keep in mind that any package listed as a dev dependency is usually intended and relevant only during development, not in a production environment. Both versions are equipped with tools like postcss-load-config and @rollup/plugin-node-resolve that support advanced use cases like CSS processing and seamless integration with Node.js modules. Developers should migrate to the latest patch version available to ensure the have all the improvements.
All the vulnerabilities related to the version 4.3.0 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.