Esbuild version 0.14.54 represents a minor update over its predecessor, version 0.14.53, in the fast and efficient JavaScript and CSS bundler landscape. While the core functionality remains consistent, reflected in identical descriptions and repository details, the key difference lies in the updated dependency versions of platform-specific builds. Both versions bundle pre-built binaries for a vast array of operating systems and architectures, encompassing Linux (across various architectures like x86, ARM, s390x, ppc64le, riscv64, loong64, and mips64le), macOS (both x64 and ARM64), Windows (x86, x64, and ARM64), and others, like Android, FreeBSD, NetBSD, SunOS and OpenBSD. This ensures comprehensive support across development environments. Developers using esbuild should note that upgrading from 0.14.53 to 0.14.54 primarily involves updated binaries for these target platforms. This most likely includes bug fixes, performance and security improvements specific to each platform’s binary. The updated release date (August 8, 2022, versus August 2, 2022) hints at recency and potential hotfixes incorporated within the platform-specific builds. Therefore, consider updating to benefit from these under-the-hood enhancements, especially if targeting diverse deployment environments. Esbuild's commitment to performance and broad platform support is maintained in the update.
All the vulnerabilities related to the version 0.14.54 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.