Esbuild, a blazing-fast JavaScript and CSS bundler, released version 0.15.1 shortly after 0.15.0, suggesting a quick fix or minor update. Both versions boast identical core dependencies and optional dependencies, spanning a wide range of operating systems and architectures. This extensive support ensures esbuild can be used across diverse development and deployment environments. The dependencies include platform-specific builds like "esbuild-linux-64," "esbuild-darwin-arm64," and "@esbuild/linux-loong64," indicating that the package bundles pre-compiled binaries for various systems, optimizing performance and simplifying installation.
The key difference resides in the version numbers of the dependencies themselves. While esbuild 0.15.0 relies on dependencies at version 0.15.0, the newer version, 0.15.1, updates those dependencies to version 0.15.1. Developers should be mindful that using a newer version automatically updates the sub-packages and fixes that come along with it so it is advised to upgrade to the latest one as soon as possible which in this case is 0.15.1. If you're already using esbuild, consider upgrading to 0.15.1 to potentially resolve bugs or benefit from performance improvements within those platform-specific components.
Both releases maintain the same MIT license and source code repository, assuring developers of continued open-source access and contribution possibilities. The distribution information also shows consistent file counts and unpacked sizes, meaning the core footprint and features remain largely unchanged between the two versions. The release dates highlight the rapid succession, emphasizing the importance of staying updated with the latest fixes and enhancements.
All the vulnerabilities related to the version 0.15.1 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.