Esbuild versions 0.4.10 and 0.4.11 represent incremental updates to this blazing-fast JavaScript bundler and minifier, designed for developers who prioritize speed and efficiency in their build processes. Both versions, licensed under MIT, share the same core description and repository information, indicating a consistent commitment to its open-source nature and continued development. The package structure remains identical with a file count of 6 and an unpacked size of 20806 bytes.
The primary distinction lies in their release dates. Version 0.4.11 was published on June 8, 2020, at 20:49:48.242Z, whereas version 0.4.10 came out earlier the same day at 11:56:45.677Z. This suggests that 0.4.11 likely contains bug fixes, minor enhancements, or potentially addresses urgent issues identified shortly after the release of 0.4.10.
For developers using esbuild, upgrading from 0.4.10 to 0.4.11 is recommended to ensure they are benefiting from the most up-to-date improvements and stability fixes. While specific details concerning changes between these minor releases aren't provided in the metadata, the rapid succession of releases implies that the update would be beneficial. Always consult the official changelog or repository commit history for a comprehensive understanding of the alterations. Esbuild remains a potent tool for optimizing web development workflows by minimizing bundle sizes and decreasing build times.
All the vulnerabilities related to the version 0.4.11 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.