@babel/runtime-corejs2 provides modular runtime helpers for Babel, incorporating core-js@2 for polyfilling. Comparing versions 7.4.5 and 7.4.4 reveals subtle but important differences for developers utilizing Babel for JavaScript compilation. Both versions share the same core dependencies: core-js@2.6.5, ensuring support for older JavaScript environments through polyfills, and regenerator-runtime@0.13.2, crucial for enabling async/await functionality in older browsers. The devDependencies also remain consistent, with @babel/helpers@^7.4.4 used during development. The license is MIT for both.
However, the key distinction lies in the releaseDate. Version 7.4.5 was released on May 21, 2019, while version 7.4.4 was released on April 26, 2019. While the fileCount and unpackedSize are the same, these differences often hint at bug fixes, performance improvements, or minor adjustments under the hood. For developers, upgrading to the latest patch version, in this case, 7.4.5, is generally recommended. While the changelog might not explicitly detail major feature additions, stability fixes are crucial for smoother development workflows and consistent application behavior. This ensures that your project benefits from the most up-to-date and reliable runtime environment provided by Babel. Regular updates to runtime libraries like @babel/runtime-corejs2 contribute to a more robust and maintainable codebase.
All the vulnerabilities related to the version 7.4.5 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.