Tsup version 6.0.0 introduces incremental improvements over the previous stable version, 5.12.9, continuing its focus on streamlining TypeScript builds. While the core functionality remains consistent, reflected in mostly unchanged dependencies and devDependencies, developers will notice subtle differences that contribute to an optimized build experience. Both versions leverage the same robust set of tools like esbuild, Rollup, and Sucrase for efficient code transformation and bundling. The peer dependencies, ensuring compatibility with specific versions of PostCSS, SWC core, and TypeScript, are also identical.
A notable difference is the slightly increased unpacked size of version 6.0.0 (477805 bytes) compared to version 5.12.9 (476279 bytes), though the file count is slightly reduced, suggesting minor internal adjustments or additions. While these differences are not major, they could reflect optimizations or new features that contribute to the overall stability and performance. Both versions are licensed under MIT and authored by EGOIST, ensuring open-source flexibility. Developers can continue expecting fast and efficient builds with either version, but the upgrade to 6.0.0 may offer marginal improvements or bug fixes contributing to a smoother developer workflow. As always, reviewing the changelog and release notes is advisable before upgrading to understand all specific changes.
All the vulnerabilities related to the version 6.0.0 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.