Babel-preset-react-app versions 9.1.0 and 9.0.2 offer developers pre-configured Babel settings optimized for Create React App projects, streamlining the process of transforming modern JavaScript and JSX code into browser-compatible formats. Version 9.1.0 introduces several Babel dependency updates focusing on bug fixes and new features while maintaining backward compatibility, creating a faster and better experience for the developer. Key updates include upgrades to @babel/core, @babel/runtime, @babel/preset-env, @babel/preset-react, @babel/preset-typescript, @babel/plugin-transform-runtime, @babel/plugin-proposal-decorators, @babel/plugin-syntax-dynamic-import, @babel/plugin-transform-destructuring, @babel/plugin-proposal-class-properties, @babel/plugin-proposal-numeric-separator, @babel/plugin-proposal-optional-chaining, @babel/plugin-transform-flow-strip-types, @babel/plugin-proposal-object-rest-spread, @babel/plugin-transform-react-display-name, and the addition of @babel/plugin-proposal-nullish-coalescing-operator. Developers using the latest version benefit from improved support for newer JavaScript syntax, enhanced performance during the compilation process, and access to cutting-edge language features like nullish coalescing. While version 9.0.2 provides a solid foundation with older Babel dependencies and plugins, users looking for the most up-to-date features and performance improvements should upgrade to version 9.1.0. Both versions simplify Babel configuration, allowing developers to concentrate on building their React applications.
All the vulnerabilities related to the version 9.1.0 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.