Tsup is a zero-config Typescript bundler powered by esbuild, designed for creating modern JavaScript libraries and applications. Version 4.8.12 improves upon the already robust foundation of 4.8.11 with a key dependency update: specifically upgrading esbuild from version 0.9.2 to 0.9.3. While seemingly minor, such patch updates in esbuild can bring significant performance and stability improvements, particularly in build times, bug fixes, and potentially even smaller bundle sizes – all crucial for developers focused on optimizing their workflow and user experience. Under the hood the library uses Rollup, Sucrase and other tools to help with the build process. Developers using Tsup benefit from its simplicity: minimal configuration is required to bundle projects for various environments. The underlying architecture using esbuild ensures fast builds for quicker iteration cycles. Both versions share a common set of dependencies including cac, chalk, debug, and rollup. Moreover, both versions share the same peer dependency requiring Typescript v4.2.3. By choosing either of these recent versions, developers are opting for a streamlined and efficient build process, contributing to a better overall development experience, especially for projects of significant scale or those requiring swift turnaround times. The difference between the unpacked size indicates that the newer version include possibly small changes, such as bug fixes, or minor performance improvement.
All the vulnerabilities related to the version 4.8.12 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.