@babel/runtime versions 7.7.6 and 7.7.5 are closely related releases of Babel's modular runtime helpers, designed to provide pre-compiled, reusable code for features like async/await, generators, and class properties, ensuring smaller bundle sizes and improved performance in JavaScript projects compiled with Babel. Both versions share the same core dependencies, relying on "regenerator-runtime" for generator functions and "@babel/helpers" for underlying helper functions. They also maintain the same MIT license and are developed within the Babel project, accessible via the same GitHub repository. Sebastian McKenzie is the listed author for both.
A key difference lies in the release date, with version 7.7.6 released on December 7, 2019, following version 7.7.5 released on December 6, 2019, indicating a quick follow-up release. Another subtle distinction is the unpacked size of the package, slightly smaller for version 7.7.6 (90767 bytes) compared to version 7.7.5 (90797 bytes). This suggests minimal modifications, potentially bug fixes or very minor optimizations, between the two versions. For developers, upgrading from 7.7.5 to 7.7.6 likely involves minimal risk and potentially offers slight improvements. It's always advisable to consult the Babel changelog for a comprehensive understanding of all changes, however, given the small difference in unpacked size, the update seems to be a patch update and the impact on functionality is expected to be low.
All the vulnerabilities related to the version 7.7.6 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.