Esno is a lightweight and efficient tool designed to run TypeScript and JavaScript Node.js applications using the power of esbuild. Comparing version 0.11.0 with the previous stable release, 0.10.1, reveals a subtle yet significant update, primarily concerning a dependency. Both versions share the core functionalities and dependencies like esbuild for blazing-fast builds, cross-spawn for cross-platform process management, and esbuild-register for on-the-fly transpilation. Developers familiar with esno will appreciate the continued stability and ease of use.
The key difference lies in the esbuild-node-loader dependency. Version 0.11.0 upgrades this dependency from version 0.4.2 to version 0.5.0. This enhancement likely brings improvements in how esbuild handles module loading within Node.js, potentially addressing edge cases or improving performance during the module resolution process. While the other dependencies remain consistent, this update suggests a focus on refining the internal workings for a smoother developer experience.
For those considering esno, it offers a compelling alternative to traditional ts-node setups, providing significantly faster startup times and improved build performance thanks to esbuild. The consistent developer experience between 0.10.1 and 0.11.0 indicates a mature project focused on incremental improvements and stability. Therefore, users can confidently upgrade to version 0.11.0, benefiting from the enhanced module loading capabilities and continued support for efficient TypeScript/JavaScript execution. Both versions are excellent choices for speeding up development workflows with Node.js and TypeScript.
All the vulnerabilities related to the version 0.11.0 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.