Esbuild 0.8.46 builds upon the foundation of its predecessor, version 0.8.45, maintaining its core identity as an exceptionally fast JavaScript bundler and minifier. Both versions are licensed under the MIT license, ensuring developers can freely use and integrate esbuild into their projects. They both share the same code repository on GitHub, reflecting a continuous development process. The distribution details, including the number of files (6) and unpacked size (71,765 bytes), are identical, suggesting that the changes between the two versions are likely focused on bug fixes, performance improvements, or minor feature enhancements rather than substantial structural alterations or the addition of new dependencies.
The key difference lies in their release dates. Version 0.8.46 was released on February 14, 2021, while version 0.8.45 was released on February 13, 2021. This suggests a very rapid iteration cycle. For developers, this quick turnaround indicates a commitment to addressing issues and swiftly incorporating user feedback. While the specific changes between these versions aren't detailed in the provided data, developers should consult the official esbuild changelog to understand the exact nature of the updates. This will help determine whether upgrading to the latest version (0.8.46) is necessary for their specific use case. If developers were experiencing issues or require specific enhancements present in the newer version, the upgrade is recommended to leverage the bug fixes and potential performance gains.
All the vulnerabilities related to the version 0.8.46 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.