Esbuild version 0.14.11 refines the popular JavaScript and CSS bundler, building upon the capabilities of its predecessor, version 0.14.10. Both releases maintain the core promise of extreme speed and efficiency, making them compelling choices for developers seeking fast build times. Examining the metadata, the key difference lies in the version numbers of the platform-specific binary dependencies. Both versions depend on the same set of platform-specific binaries like esbuild-linux-64, esbuild-darwin-arm64, and esbuild-windows-64, however, version 0.14.11 utilizes the 0.14.11 versions of these binaries, while 0.14.10 uses the 0.14.10 versions. This indicates that the newer release likely includes bug fixes, performance improvements, or compatibility updates within these pre-built binaries tailored for various operating systems and architectures. The difference of unpacked size of the tarball, being slightly larger in the newer version (108983 vs 108715), also sugests some changes happened between the two versions and are related to the binaries. For developers, upgrading to 0.14.11 is recommended to leverage the latest enhancements. The update process is straightforward, involving a simple npm install esbuild@latest. For those already using a specific version, updating ensures access to the most current optimizations and potentially resolves any platform-specific issues encountered in earlier releases. Always consult the official esbuild changelog for a detailed breakdown of the changes included in version 0.14.11, for a full understanding of the scope of changes.
All the vulnerabilities related to the version 0.14.11 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.