Esbuild version 0.16.4 represents a minor update over its predecessor, 0.16.3, in the rapidly evolving landscape of JavaScript and CSS bundlers. Both versions maintain the core promise of esbuild: exceptional speed and efficiency in bundling and minifying web assets, making it a compelling choice for developers seeking to optimize build times.
The primary difference lies in the versioning of the dependencies. Both dependencies and optionalDependencies in version 0.16.4 have been updated to point to version 0.16.4 of their respective platform-specific packages such as @esbuild/linux-x64 and @esbuild/darwin-arm64. This indicates that the update likely includes bug fixes, performance improvements, or platform-specific adaptations within these lower-level components. While the core API and functionality of esbuild might remain consistent between the two versions, developers should consider upgrading to 0.16.4 to benefit from the most recent optimizations and stability enhancements introduced in the underlying platform-specific binaries.
For developers, the key takeaway is a commitment from the esbuild team to ongoing improvement and support across a wide range of operating systems and architectures. If you're experiencing issues on a specific target platform, or simply want to ensure you're using the most up-to-date version with potential performance gains, upgrading from 0.16.3 to 0.16.4 is recommended. The identical fileCount and unpackedSize suggest only minimal changes under the hood. The releaseDate also shows the new version came out soon after the other, suggesting that the changes were important. Finally, remember that esbuild, in general, provides a dramatically faster bundling experience compared to older tools like Webpack, facilitating faster and more iterative development cycles.
All the vulnerabilities related to the version 0.16.4 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.