Esbuild version 0.14.37 represents a minor update over its predecessor, version 0.14.36, in the fast JavaScript and CSS bundler ecosystem. The core functionality, focused on speed and efficiency in bundling and minifying web assets, remains consistent between the two versions. Developers familiar with 0.14.36 will find a seamless transition to 0.14.37.
The key difference lies primarily in the dependency versions of platform-specific binaries. Both versions list identical dependencies and optional dependencies, covering a wide range of operating systems and architectures, including Linux (32-bit, 64-bit, ARM, ARM64, s390x, ppc64le, riscv64, mips64le), macOS (64-bit, ARM64), Windows (32-bit, 64-bit, ARM64), Android (64-bit, ARM64), FreeBSD (64-bit, ARM64), NetBSD (64-bit), SunOS (64-bit), and OpenBSD (64-bit). However, in the newer version each of this dependencies are updated too.
Developers should note that the releaseDate field indicates a more recent release for version 0.14.37, implying potential bug fixes, performance enhancements, or compatibility adjustments made since the previous version. While the core API and usage patterns are unlikely to have changed drastically, upgrading to the latest patch version is generally recommended to benefit from the latest improvements and ensure optimal performance and security, particularly in production environments because the esbuild dependencies are critical. Check the esbuild changelog for detailed information.
All the vulnerabilities related to the version 0.14.37 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.