Esbuild version 0.11.14 is a minor update to the exceptionally fast JavaScript bundler and minifier, building upon the foundation laid by version 0.11.13. Both versions share the same core characteristics: the lightning-fast bundling speed that developers rave about, efficient minification capabilities, the MIT license promoting open use, and the same source code repository on GitHub. They are also similar in size, with equivalent fileCount and unpackedSize.
The key difference lies in the release date. Version 0.11.14 was published on April 24, 2021, a single day after version 0.11.13's release on April 23, 2021. This suggests that version 0.11.14 likely incorporates bug fixes or minor improvements discovered shortly after the previous release.
For developers considering adopting esbuild, or those already using version 0.11.13, upgrading to version 0.11.14 is generally recommended. The update offers potential stability enhancements and refinements without introducing breaking changes or significantly altering the existing API. While the changes between these specific versions are subtle, staying up-to-date ensures you benefit from the latest improvements to this blazing-fast bundler. Esbuild facilitates a dramatically faster development workflow thanks to the rapid bundling and minification of your front-end assets, making it a valuable tool for any JavaScript project.
All the vulnerabilities related to the version 0.11.14 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.