Esbuild versions 0.6.13 and 0.6.14 are both iterations of the exceptionally swift JavaScript bundler and minifier renowned for its speed and efficiency. Both versions share the same core characteristics: MIT licensing, a GitHub repository managed by Evan Wallace, a fileCount of 6, and an identical unpackedSize of 29538 bytes. Considering this commonality, developers can expect comparable performance and resource usage from both versions for basic bundling and minification tasks.
The primary difference lies in their release dates, with version 0.6.14 being released on August 2, 2020, and version 0.6.13 on July 31, 2020. This suggests that version 0.6.14 likely contains bug fixes, minor enhancements, or small optimizations implemented after the release of 0.6.13. While the specifics of these changes aren't detailed in the provided metadata, developers should upgrade to version 0.6.14 to benefit from the latest improvements and stability enhancements. For projects sensitive to subtle changes or requiring maximum stability, carefully reviewing the changelog or release notes accompanying version 0.6.14 is recommended to understand the precise modifications and ensure compatibility. Esbuild, in general, is a worthy tool to improve the build and deploy pipeline, saving developer's precious time.
All the vulnerabilities related to the version 0.6.14 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.