Esbuild version 0.14.23 represents a minor update to the popular JavaScript and CSS bundler, building upon the solid foundation of version 0.14.22. Both versions maintain the core promise of extreme speed in bundling and minification, which is a key selling point for developers seeking to optimize their build processes. The primary distinction lies in the versioning of the platform-specific binaries included as dependencies and optional dependencies. Each binary, such as esbuild-linux-64, esbuild-windows-64, and esbuild-darwin-arm64, is bumped from version 0.14.22 to 0.14.23 to match the main esbuild package version.
For developers, this update likely includes bug fixes and minor improvements within these platform-specific binaries. While the unpacked size and file count remain consistent between the two versions, suggesting no significant architectural changes, the updated binaries ensure compatibility and stability across different operating systems and architectures. The release date difference indicates that 0.14.23 follows shortly after 0.14.22, hinting at a quick fix or refinement release. Developers may want to upgrade to version 0.14.23 to benefit from the latest optimizations and bug fixes targeted for their specific environments, ensuring a smooth and reliable bundling experience.
All the vulnerabilities related to the version 0.14.23 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.