Esbuild is an extremely fast JavaScript and CSS bundler and minifier. Looking at the difference between versions 0.14.13 and 0.14.14, the core functionalities remain the same. Most notably the dependencies and optional dependencies all received a bumped version. This concerns the platform-specific builds, like esbuild-linux-64, esbuild-darwin-arm64, and esbuild-windows-64, among many others, reflecting updates and improvements tailored to these specific environments.
This means that developers using esbuild across different operating systems and architectures stand to benefit from the enhancements integrated within these platform-specific packages. These improvements could include bug fixes, performance optimizations, or expanded support for new features or hardware capabilities on each platform.
Apart from the version bumps in dependencies, the description, license, repository, and fileCount remain constant, showing a consistent approach to the core aspects of the package. The only other major difference is the releaseDate which shows that 0.14.14 got released a few days after 0.14.13 and a slightly different unpackedSize . The developers, though, will appreciate the continual optimization and platform-specific build improvements across different environments. This is consistent with the Esbuild philosophy which focuses on speed and efficiency across all platforms.
All the vulnerabilities related to the version 0.14.14 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.