Babel Preset React App saw a significant update moving from version 6.1.0 to 7.0.0, offering developers an enhanced and more refined set of tools for modern React development. The primary function of this package remains consistent: to provide a pre-configured Babel setup tailored for Create React App projects, simplifying the often-complex process of transpiling JavaScript code.
Key improvements focused on dependency updates. Version 7.0.0 incorporated newer versions of several core Babel packages. Notably, @babel/core was updated from 7.1.0 to 7.1.6 and @babel/runtime went from 7.0.0 to 7.1.5, while @babel/preset-env also advanced to 7.1.6. These updates ensured developers benefited from the latest bug fixes, performance improvements, and feature enhancements within the Babel ecosystem. Minor updates were also deployed on @babel/plugin-proposal-decorators and @babel/plugin-transform-destructuring.
Furthermore, babel-plugin-transform-react-remove-prop-types was bumped from version 0.4.18 to 0.4.20. These incremental upgrades helped to keep your projects aligned with industry best practices and ensure compatibility with the evolving landscape of JavaScript and React. Overall, the upgrade to version 7.0.0 represents a commitment to providing Create React App users with a stable, up-to-date, and optimized Babel configuration.
All the vulnerabilities related to the version 7.0.0 of the package
Babel has inefficient RegExp complexity in generated code with .replace when transpiling named capturing groups
When using Babel to compile regular expression named capturing groups, Babel will generate a polyfill for the .replace method that has quadratic complexity on some specific replacement pattern strings (i.e. the second argument passed to .replace).
Your generated code is vulnerable if all the following conditions are true:
.replace method on a regular expression that contains named capturing groups.replaceIf you are using @babel/preset-env with the targets option, the transform that injects the vulnerable code is automatically enabled if:
You can verify what transforms @babel/preset-env is using by enabling the debug option.
This problem has been fixed in @babel/helpers and @babel/runtime 7.26.10 and 8.0.0-alpha.17, please upgrade. It's likely that you do not directly depend on @babel/helpers, and instead you depend on @babel/core (which itself depends on @babel/helpers). Upgrading to @babel/core 7.26.10 is not required, but it guarantees that you are on a new enough @babel/helpers version.
Please note that just updating your Babel dependencies is not enough: you will also need to re-compile your code.
If you are passing user-provided strings as the second argument of .replace on regular expressions that contain named capturing groups, validate the input and make sure it does not contain the substring $< if it's then not followed by > (possibly with other characters in between).
This vulnerability was reported and fixed in https://github.com/babel/babel/pull/17173.