Esbuild version 0.23.0 represents a minor update to the blazingly fast JavaScript and CSS bundler and minifier, building upon the foundation laid by version 0.22.0. While the core functionality and description remain consistent – promising speed and efficiency in bundling web assets – a key difference lies in the version bump of the optional dependencies. Both versions share an identical set of optional dependencies, targeting specific operating systems and architectures such as AIX, Linux (various architectures), SunOS, Windows, Darwin, and FreeBSD, enabling esbuild to function optimally across diverse platforms. These dependencies, named like @esbuild/linux-x64, are now updated to version 0.23.0, aligning with the main package version. This update likely incorporates platform-specific optimizations, bug fixes, or compatibility enhancements, ensuring a smoother experience for developers deploying esbuild in these environments.
Furthermore, examining the releaseDate reveals that version 0.23.0 was released on July 2nd, 2024, succeeding version 0.22.0, which was released on June 30th, 2024. The dist details show the fileCount and unpackedSize are the same. Developers should upgrade to version 0.23.0 to benefit from the latest improvements and ensure compatibility. The MIT license and repository URL remain unchanged, indicating continuity in licensing and source code management.
All the vulnerabilities related to the version 0.23.0 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.