Babel Preset React App streamlines the process of configuring Babel for React projects, particularly for those using Create React App. Version 7.0.1 introduces several updates and improvements compared to its predecessor, version 7.0.0, impacting developers who rely on this preset for their JavaScript transformations.
The most notable changes lie within the dependency updates. Version 7.0.1 upgrades core Babel packages such as @babel/core (from 7.1.6 to 7.2.2), @babel/preset-env (from 7.1.6 to 7.3.1), and @babel/runtime (from 7.1.5 to 7.3.1). Each of these updates include bug fixes, performance improvements, and potentially new ECMAScript features support. Developers will also appreciate the updated versions of @babel/plugin-transform-classes, @babel/plugin-transform-runtime, @babel/plugin-proposal-decorators, @babel/plugin-transform-destructuring, @babel/plugin-proposal-class-properties, @babel/plugin-transform-flow-strip-types, @babel/plugin-proposal-object-rest-spread, @babel/plugin-transform-react-display-name, and @babel/plugin-transform-react-constant-elements. Plugin updates typically address specific code transformation edge cases to ensure correct transpilation of modern JavaScript. Babel-loader bumps up version from 8.0.4 to 8.0.5 and babel-plugin-macros gets a minor upgrade from 2.4.2 to 2.5.0.
These dependency upgrades result to better support for newer JavaScript syntax and features and likely improved build times thanks to optimizations within Babel and its plugins. Developers should upgrade to version 7.0.1 of the babel-preset-react-app to leverage these improvements and address potential compatibility issues with the latest JavaScript standards.
All the vulnerabilities related to the version 7.0.1 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.