Esbuild 0.14.3 and 0.14.2 are both versions of an extremely fast JavaScript and CSS bundler and minifier, designed to streamline web development workflows. Examining the package data, the core difference lies in the versioning of their dependencies. Both versions list identical sets of dependencies and optional dependencies, covering a wide array of operating systems and architectures including Linux (32-bit, 64-bit, ARM, ARM64, PPC64le, MIPS64le), SunOS (64-bit), Darwin (64-bit, ARM64), NetBSD (64-bit), FreeBSD (64-bit, ARM64), OpenBSD (64-bit), Android (ARM64) and Windows (32-bit, 64-bit, ARM64). However, version 0.14.3 depends on and optionally depends on versions "0.14.3" of these platform-specific packages, while version 0.14.2 relies on "0.14.2" of the same packages.
This means the core esbuild package (0.14.3) incorporates potentially bug fixes, performance improvements, or minor feature additions within these platform-specific binaries compared to the prior release. The update from 0.14.2 to 0.14.3 likely addresses specific issues or enhances functionality exposed during the week of development time between releases, reflected by the differing releaseDate values. For developers, upgrading from 0.14.2 to 0.14.3 is recommended to ensure access to the latest refinements across supported platforms. The 'dist' data shows tiny differences in unpackedSize which might indicate that 0.14.3 has more features or minor changes that increased its size.
All the vulnerabilities related to the version 0.14.3 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.