Esbuild version 0.19.2 is a minor update to the extremely fast JavaScript and CSS bundler and minifier, succeeding version 0.19.1. Both versions maintain the core promise of rapid build times and efficient code optimization. The primary distinction lies in the updated versions of esbuild's platform-specific binaries. Both the dependencies and optionalDependencies sections reflect this, with all @esbuild/* packages moving from version 0.19.1 to 0.19.2. This indicates bug fixes and potentially performance enhancements tailored to specific operating systems and architectures, encompassing Linux (various architectures), Windows, macOS, Android, FreeBSD, NetBSD, SunOS, and OpenBSD.
For developers, this means a smoother and potentially more stable experience across different environments. Upgrading from 0.19.1 to 0.19.2 ensures you benefit from the latest platform-specific improvements. While the core bundling and minification logic likely remains consistent between the two versions, these binary updates can address compatibility issues or boost performance in certain deployment scenarios. The unchanged license, repository, fileCount and unpackedSize suggest no significant changes in licensing, project structure, or overall file size. Finally, the release dates show that 0.19.2 was released just a few days after 0.19.1, indicative of a quick patch or refinement.
All the vulnerabilities related to the version 0.19.2 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.