Esbuild version 0.14.0 represents an incremental update over the previous stable version, 0.13.15, primarily focusing on internal improvements and bug fixes. The core functionality remains consistent, ensuring a smooth transition for developers already using esbuild for JavaScript and CSS bundling and minification. Both versions share the same MIT license and repository, indicating a commitment to open-source development.
The key difference lies in the updated dependencies. Both versions list identical sets of platform-specific esbuild binaries (e.g., esbuild-linux-64, esbuild-windows-64) for various operating systems and architectures. However, version 0.14.0 references version "0.14.0" of these binaries, while version 0.13.15 references version "0.13.15". This indicates that the underlying compiled binaries have been updated to reflect the changes in the newer esbuild release.
For developers, this means that upgrading to 0.14.0 likely incorporates performance enhancements, bug resolutions, and compatibility updates within the core esbuild engine. While the API and core features remain consistent, the newer binaries are designed to provide a more robust and optimized bundling experience. The small increase in unpackedSize from 104295 to 104346 suggests minor changes in the binary files, confirming the update. The release date difference provides a timeline for when these improvements became available. Therefore, upgrading can bring subtle yet beneficial improvements without requiring significant code modifications. Always check the official changelog for detailed information on specific fixes and enhancements.
All the vulnerabilities related to the version 0.14.0 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.