@babel/runtime versions 7.12.1 and 7.12.0 are incremental releases providing Babel's modular runtime helpers, crucial for enabling modern JavaScript features in environments that don't natively support them. Both versions, licensed under MIT, depend on regenerator-runtime (version ^0.13.4) for async/await functionality. The primary distinction lies in their dependency makeup: version 7.12.0 includes a dev dependency on "@babel/helpers" (version ^7.10.4), which is absent in 7.12.1. This suggests a possible shift in how these helpers are integrated during development or a potential optimization in the build process.
Developers should note that while the file count remains consistent at 165, the unpacked size slightly decreases from 113026 bytes in 7.12.0 to 113001 bytes in 7.12.1, indicating minor size optimizations. Released just a day apart (October 14th and 15th, 2020), the 7.12.1 release likely addresses a specific issue, bug fix, or minor optimization discovered shortly after the 7.12.0 release. For consumers of @babel/runtime, upgrading to 7.12.1 is advisable for potentially improved stability and a slightly smaller footprint, without any breaking changes apparent from the dependency differences. This package remains essential for projects leveraging Babel to transpile code for broader compatibility.
All the vulnerabilities related to the version 7.12.1 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.