Esbuild version 0.13.0 introduces a significant update to this high-performance JavaScript bundler and minifier, building upon the foundations of its predecessor, version 0.12.29. Both versions share the same core description, MIT license, and repository, emphasizing the project's commitment to speed and efficiency in web development workflows. The key difference lies in the set of dependencies and optional dependencies included in version 0.13.0.
Specifically, version 0.13.0 enumerates a comprehensive list of platform-specific binaries as dependencies and optional dependencies. These include esbuild-linux-32, esbuild-linux-64, esbuild-sunos-64, esbuild-darwin-64, esbuild-linux-arm, esbuild-freebsd-64, esbuild-openbsd-64, esbuild-windows-32, esbuild-windows-64, esbuild-linux-arm64, esbuild-darwin-arm64, esbuild-android-arm64, esbuild-freebsd-arm64, esbuild-linux-ppc64le, esbuild-windows-arm64, and esbuild-linux-mips64le, all at version 0.13.0. This comprehensive listing signifies an improved mechanism for distributing platform-specific builds, ensuring that esbuild can seamlessly operate across a wide range of operating systems and architectures. Developers benefit from this enhanced support, as it simplifies the installation process and reduces the likelihood of compatibility issues during deployment. The updated releaseDate and slightly increased unpackedSize in version 0.13.0 also suggest underlying improvements and potentially new features that contribute to the overall performance and stability.
All the vulnerabilities related to the version 0.13.0 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.