Esbuild version 0.14.53 is a minor release succeeding version 0.14.52 of this extremely fast JavaScript and CSS bundler and minifier. The core functionality remains consistent, focusing on rapid build times and efficient code optimization. Developers familiar with esbuild will find the upgrade seamless.
The primary distinction lies in the updated dependency versions of platform-specific binaries. Both versions list identical dependencies and optional dependencies, with each dependency package being specific to an operating system and architecture combination, indicating esbuild’s dedication to providing optimized builds for diverse environments.
The key takeaway for developers is that upgrading to 0.14.53 ensures they are leveraging the latest platform-specific optimizations and potential bug fixes within those binaries, but without any major impact. This includes binaries for Linux (32-bit, 64-bit, ARM, ARM64, s390x, ppc64le, riscv64, LoongArch64, and mips64le), macOS (64-bit and ARM64), Windows (32-bit, 64-bit, and ARM64), SunOS (64-bit), NetBSD (64-bit), Android (64-bit and ARM64), FreeBSD (64-bit and ARM64), and OpenBSD (64-bit). The "releaseDate" field shows that the new version was released approximately 26 minutes after the previous one, suggesting the changes were urgent bug fixes or other important improvements to the platform specific binaries. While the fileCount remains stable at 7, there's a slight increase in unpackedSize (from 119585 to 119589) pointing towards potentially larger binaries required by this new version.
All the vulnerabilities related to the version 0.14.53 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.