@babel/runtime is a crucial package for Babel users, providing modular runtime helpers necessary for transformed code to execute correctly across different environments. Examining versions 7.26.0 and 7.26.7 reveals subtle but potentially important differences for developers.
Both versions share the same core functionality and dependencies; both rely on regenerator-runtime version ^0.14.0 and are under the MIT license. They are both maintained by the Babel team and found in the same repository location on GitHub. This indicates a consistent and well-maintained library.
The key difference lies in the unpacked size and release date. Version 7.26.7, released on January 24, 2025 has an unpacked size of 248,428 bytes, while version 7.26.0, released on October 25, 2024, has an unpacked size of 248,404 bytes; this means there is very little difference in size (24 bytes) that is likely related to bugfixes or minor changes to the runtime, so for anyone seeking the most up-to-date fixes and improvements, upgrading to version 7.26.7 is advisable, however there no major changes related to feature set, if version 7.26.0 is used now, there is no urgent need to updated it. Always check the official Babel changelog for detailed information on the specific changes introduced in each patch release.
All the vulnerabilities related to the version 7.26.7 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.