Esbuild is a blazing-fast JavaScript bundler and minifier. Comparing versions 0.1.16 and 0.1.15, developers will find the core functionality remains consistent. Both versions, licensed under MIT, provide efficient bundling and minification, boasting extremely fast performance. The small unpacked size of 2463 bytes and a mere 3 files, speak to the lean and efficient nature of Esbuild which is great for optimized performance.
The key difference lies in the release date. Version 0.1.16 was released on April 23, 2020, while version 0.1.15 was released earlier on April 22, 2020. This one-day gap suggests that version 0.1.16 likely includes minor bug fixes, performance improvements, or very small feature additions compared to its predecessor. The difference of one day between releases also suggests that any change or updates would likely be minor and non-breaking.
Developers should generally opt for the latest version (0.1.16) to benefit from any bug fixes or subtle improvements. When choosing the version, it is important to align with any related dependencies that may have version constraints. The esbuild library would be a great option for JavaScript project due to the library's speed and because it is lightweight. Note the repository URL for more information.
All the vulnerabilities related to the version 0.1.16 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.