CVE-2025-27789

Inefficient RexExp complexity in generated code with .replace when transpiling named capturing groups

Description

Babel is a compiler for writing next generation JavaScript. When using versions of Babel prior to 7.26.10 and 8.0.0-alpha.17 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`). Generated code is vulnerable if all the following conditions are true: Using Babel to compile regular expression named capturing groups, using the `.replace` method on a regular expression that contains named capturing groups, and the code using untrusted strings as the second argument of `.replace`. This problem has been fixed in `@babel/helpers` and `@babel/runtime` 7.26.10 and 8.0.0-alpha.17. It's likely that individual users do not directly depend on `@babel/helpers`, and instead depend on `@babel/core` (which itself depends on `@babel/helpers`). Upgrading to `@babel/core` 7.26.10 is not required, but it guarantees use of a new enough `@babel/helpers` version. Note that just updating Babel dependencies is not enough; one will also need to re-compile the code. No known workarounds are available.

Category

6.2
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.02%
Affected: babel babel
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2025-27789?
CVE-2025-27789 has been scored as a medium severity vulnerability.
How to fix CVE-2025-27789?
To fix CVE-2025-27789, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-27789 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2025-27789 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-27789?
CVE-2025-27789 affects babel babel.
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