@babel/runtime provides modular runtime helpers for Babel, allowing developers to use cutting-edge JavaScript features without bloating their final bundle size. Comparing versions 7.8.4 and 7.8.7 reveals a subtle yet important update: a dependency upgrade for regenerator-runtime. Version 7.8.7 depends on regenerator-runtime ^0.13.4, while the older 7.8.4 relies on regenerator-runtime ^0.13.2. This seemingly minor change likely incorporates bug fixes and potentially performance improvements within the regenerator-runtime library, which is crucial for enabling async/await functionality in older JavaScript environments. Consequently, developers upgrading to @babel/runtime 7.8.7 can expect enhanced stability and potentially better performance when using asynchronous JavaScript features transpiled by Babel. Both versions share identical development dependencies (@babel/helpers":"^7.8.4), license (MIT), repository details, author information, the number of files within the package (151), and the unpacked size (90827 bytes). Therefore, the key driver for updating is leveraging the improved regenerator-runtime version, ensuring seamless and efficient execution of async/await code across various JavaScript platforms. Version 7.8.7 was released on March 5, 2020, a little over a month after v7.8.4 was released (January 30, 2020).
All the vulnerabilities related to the version 7.8.7 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.