Esbuild version 0.7.22 represents a minor update to the blazing-fast JavaScript bundler and minifier, building upon the solid foundation of version 0.7.21. Both versions, licensed under the MIT license and available on GitHub, share the same core mission: to provide developers with an extremely performant tool for bundling and minifying JavaScript code. At their core, both versions focus on extreme speed and efficiency.
The key difference between the two versions lies in subtle refinements and bug fixes. While the core functionality remains consistent, version 0.7.22 incorporates improvements that might enhance stability or address specific edge cases encountered by users of 0.7.21. From a developer perspective, it's interesting to note that both maintain a small footprint with a manageable number of files, signaling lean and optimized code. Version 0.7.22 sees a slight increase in unpackedSize to 40832 from 39872 of the previous version that is a very small increase and might be the result of some extra documentation or bug fixes.
For developers already leveraging esbuild, upgrading to 0.7.22 offers the potential for a smoother and more reliable bundling experience. While the changes may not be groundbreaking, staying up-to-date with the latest minor versions ensures access to the most refined and robust tool available. The release date difference indicates active maintenance, suggesting a responsive development team committed to ongoing improvement.
All the vulnerabilities related to the version 0.7.22 of the package
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.