@babel/runtime version 7.20.5 represents a subtle but potentially impactful update over its immediate predecessor, version 7.20.1. Both packages are essential components for Babel users, providing modular runtime helpers that enable the execution of transformed JavaScript code in various environments. Primarily, the update involves a shift in a dependency: regenerator-runtime moves from version ^0.13.10 to ^0.13.11. This seemingly small increment suggests bug fixes, performance improvements, or minor feature enhancements within the regenerator-runtime library, which manages the execution of async/await and generator functions. Developers should review the regenerator-runtime changelog for specific details about these changes to understand their potential effects on projects.
Beyond the dependency update, there are minor variations in the package distribution metadata. Version 7.20.5 includes 199 files, with an unpacked size of 219855 bytes, slightly increased from version 7.20.1 which had 197 files and weighed 218418 bytes unpacked,. This difference may point to fine-tuning of the runtime helpers or addition of polyfills. Published on November 28, 2022, version 7.20.5 followed version 7.20.1, which was released on November 1, 2022. Developers relying on async/await should carefully test their code after upgrading. While the core functionality remains consistent, such dependency updates can occasionally affect the runtime behavior of transformed code.
All the vulnerabilities related to the version 7.20.5 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.