Esbuild versions 0.6.5 and 0.6.4 are both iterations of an extremely fast JavaScript bundler and minifier, designed to significantly improve build times for web development projects. Both versions maintain the core features and licensing under the MIT license, originating from the same GitHub repository. They include very similar dist attributes, having also the same fileCount with small unpacked sizes, making them easy to include in other projects.
The primary difference lies in their release dates. Version 0.6.5 was released on July 20, 2020, while version 0.6.4 was released on July 19, 2020. This one-day gap suggests that version 0.6.5 likely contains bug fixes, performance improvements, or minor adjustments over version 0.6.4. While the provided data doesn't detail the specific changes, developers should generally opt for the newer version (0.6.5) to benefit from the latest enhancements.
For developers seeking a high-performance bundler, esbuild presents a compelling option due to its speed and efficiency. The small difference between the previous and the current version suggest that the library is under active development. Integrating esbuild into a project can lead to faster build times, improving the development workflow. Given the rapid release cycle, consult the official esbuild changelog or repository for detailed release notes to understand the specific changes between these versions and to leverage the most up-to-date features and fixes.
All the vulnerabilities related to the version 0.6.5 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.