Esbuild version 0.14.46 represents a minor update to the popular JavaScript and CSS bundler, building upon the foundation laid by version 0.14.45. Examining the package data, the core functionality and description remain consistent: an extremely fast bundler and minifier. The primary distinction lies in the version numbers of the architecture-specific dependencies. Both versions bundle platform-specific binaries ensuring compatibility across various operating systems and architectures, but 0.14.46 updates these to the 0.14.46 version, whereas 0.14.45 has 0.14.45 as dependency. This synchronization suggests bug fixes, performance improvements, or security patches within the underlying native builds. A small difference is also present on the unpackedSize.
For developers, this update should be appealing due to its focus on stability and refinement. The consistent API and core functionality mean upgrading should be seamless with minimal risk of breaking changes. The updated dependencies imply that the team behind esbuild is committed to maintaining the project ensuring the latest versions offer enhanced reliability and potentially better performance. This release, published on 2022-06-18, further solidifies esbuild's position as a modern, performant tool for web development. As a result, developers can trust that this iteration contributes to a more robust and efficient bundling process.
All the vulnerabilities related to the version 0.14.46 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.