Tsup is a zero-config TypeScript bundler powered by esbuild, designed for creating modern JavaScript libraries. Comparing versions 4.5.0 and 4.4.0, we observe subtle but important updates. Both versions share a common foundation, relying on dependencies like cac for command-line interface handling, chalk for terminal styling, rollup for bundling, and esbuild for its blazing-fast compilation speeds. The core utilities and development dependencies are identical, ensuring a consistent development experience across both versions.
However, a key difference lies in the version of esbuild itself. Version 4.5.0 bumps esbuild from 0.8.50 to 0.8.53. While seemingly minor, such point releases in esbuild often include performance enhancements, bug fixes, or support for newer ECMAScript features. Developers upgrading to tsup 4.5.0 benefit from these under-the-hood improvements in the underlying build tool.
Furthermore, the "dist" section reveals a slight increase in "unpackedSize" from 644423 to 644760 bytes, suggesting that the updated esbuild version or associated changes introduce a marginal increase in the package footprint. Despite this, Tsup remains lightweight and efficient. Finally, the release date shows that version 4.5.0 followed shortly after 4.4.0, indicating an active and responsive maintenance cycle of the library. Tsup facilitates streamlined bundling, and the differences showcase the continuous refinement of the tool.
All the vulnerabilities related to the version 4.5.0 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.