Esbuild version 0.1.25 represents a minor iteration over its predecessor, version 0.1.24, in the fast-paced world of JavaScript bundling. Both versions maintain the core promise of esbuild: an extremely fast JavaScript bundler and minifier designed to significantly improve build times for web developers. Key features like support for modern JavaScript and TypeScript, along with dead code elimination and cross-browser compatibility, remain consistent between the two versions.
The primary distinctions lie in the details. Examining the provided data reveals a small increase in unpackedSize from 8702 bytes in version 0.1.24 to 9534 bytes in version 0.1.25. This suggests the newer version includes incremental improvements and potentially new features or bug fixes that contributed to the slightly larger package size. While the fileCount remains constant at 6, the internal composition has likely shifted. Although specific changes aren't explicitly detailed, developers can anticipate refinements that enhance performance, stability, or introduce subtle enhancements. The release date difference indicates a single day between these two versions— with 0.1.25 being released after 0.1.24 — so the changes can not be massive.
For developers considering esbuild, both versions deliver on the core promise of lightning-fast bundling. The upgrade from 0.1.24 to 0.1.25 likely brings incremental improvements, and users are recommended to update to 0.1.25.
All the vulnerabilities related to the version 0.1.25 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.