Esbuild version 0.14.47 arrives as a minor update, succeeding version 0.14.46. While the core description remains consistent – portraying esbuild as an "extremely fast JavaScript and CSS bundler and minifier" – the key change lies within the version numbers of its platform-specific dependencies. Both versions bundle a comprehensive set of native binaries tailored for diverse operating systems and architectures, including Linux (32-bit, 64-bit, ARM, ARM64, s390x, ppc64le, riscv64, 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).
Crucially, the dependencies and optional dependencies in version 0.14.47 point to version "0.14.47" of the corresponding platform-specific packages, whereas 0.14.46 referenced "0.14.46". This indicates that the update primarily involves rebuilding and republishing the native binaries, possibly addressing bug fixes, performance improvements, or compatibility enhancements within those platform-specific modules. Developers should note that upgrading to 0.14.47 likely provides a more polished and reliable experience across various deployment environments. The common details between the versions are the MIT license, the link to the library's repository on GitHub, a fileCount of 7 and a similar unpacked size of around 117974. Also both versions dependencies and optional dependencies are the same.
All the vulnerabilities related to the version 0.14.47 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.