Esbuild version 0.17.5 represents a minor update over its predecessor, 0.17.4, primarily focusing on dependency adjustments. Both versions share the same core purpose: providing developers with an exceptionally fast JavaScript and CSS bundler and minifier. The description remains consistent, highlighting esbuild's speed as a core selling point. Both versions are licensed under the MIT license and are hosted on GitHub in the same repository.
The key difference lies in the versions of the platform-specific binary packages listed as dependencies and optional dependencies. Both hold the same set of included dependencies, but in version 0.17.5 they all got updated to version 0.17.5. The package contains prebuilt binaries for a wide array of operating systems and architectures, including Linux, Windows, macOS (Darwin), Android, FreeBSD, NetBSD, OpenBSD, and SunOS, covering x64, ARM, ARM64, IA32, ppc64, s390x, loong64, riscv64 and mips64el architectures. The "dependencies" and "optionalDependencies" block look identical except for the version numbers which are bumped to 0.17.5 from 0.17.4.
For developers, this implies a potential need to update their esbuild dependency to ensure compatibility and leverage any bug fixes or performance improvements introduced in the underlying platform-specific binaries. While the update is minor, staying current is generally recommended, especially when platform-specific issues are a concern. Both versions offer the same core functionality, empowering developers with fast build times for modern web development workflows. Unpacked size, file count and repository url are equal. The release date of the updated version is January 27, 2023 where the older version was released at January 22, 2023.
All the vulnerabilities related to the version 0.17.5 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.