Esbuild 0.14.41 is a minor version update to the blazing-fast JavaScript and CSS bundler, following closely on the heels of version 0.14.40. Both versions maintain the MIT license, reflecting the project's commitment to open-source principles, and are hosted in the same GitHub repository. While the descriptions remain identical, highlighting esbuild's core value proposition as an exceptionally speedy bundler and minifier, the principal difference lies in the updated dependency versions.
Specifically, all platform-specific binaries within the dependencies and optionalDependencies sections have been bumped from version 0.14.40 to 0.14.41. This includes binaries targeting a wide range of operating systems and architectures such as Linux (32-bit, 64-bit, ARM, ARM64, s390x, ppc64le, riscv64, mips64le), Windows (32-bit, 64-bit, ARM64), macOS (64-bit, ARM64), FreeBSD (64-bit, ARM64), Android (64-bit, ARM64), NetBSD (64-bit), OpenBSD (64-bit), and SunOS (64-bit).
For developers, this indicates a patch release, likely addressing bug fixes, performance improvements, or compatibility enhancements specific to those platform-dependent binaries. While the core API and bundling behavior may remain largely unchanged, upgrading from 0.14.40 to 0.14.41 is recommended to ensure the most stable and performant experience across all supported environments. The brief time difference between release dates suggests a quick follow up to 0.14.40 due a bug fix or other important reason to upgrade
All the vulnerabilities related to the version 0.14.41 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.