Vulnerabilities in pkg:npm/@babel/helpers

PACKAGE
Advisory Identifier: GHSA-968p-4wvh-cqc8
Advisory Summary

CVE-2025-27789 is a MODERATE (CVSS 6.2) babel has inefficient regexp complexity vulnerability (CWE-1333: Inefficient Regular Expression Complexity) affecting @babel/helpers libraries in the npm ecosystem. The issue involves babel has inefficient regexp complexity in generated code with .replace when transpiling named capturing groups. Remediation is available by upgrading affected packages to version 7.26.10, 8.0.0-alpha.17.

1 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:npm/@babel/helpers

1 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:npm/@babel/helpers. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-968p-4wvh-cqc8 CVE-2025-27789 MODERATE Babel has inefficient RegExp complexity in generated code with .replace when transpiling named capturing groups

CVE-2025-27789 at a Glance

CVE Identifier CVE-2025-27789
GHSA Identifier GHSA-968p-4wvh-cqc8
Severity MODERATE
CVSS v3.1 Base Score 6.2
CWE Classification CWE-1333: Inefficient Regular Expression Complexity
Affected Product @babel/helpers
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 6.2

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2025-27789

To remediate this vulnerability, upgrade all affected @babel/helpers dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

@babel/helpers fixed: 7.26.10
npm install @babel/helpers@7.26.10
@babel/runtime fixed: 7.26.10
npm install @babel/runtime@7.26.10
@babel/runtime-corejs2 fixed: 7.26.10
npm install @babel/runtime-corejs2@7.26.10
@babel/runtime-corejs3 fixed: 7.26.10
npm install @babel/runtime-corejs3@7.26.10
@babel/helpers fixed: 8.0.0-alpha.17
npm install @babel/helpers@8.0.0-alpha.17
@babel/runtime fixed: 8.0.0-alpha.17
npm install @babel/runtime@8.0.0-alpha.17
@babel/runtime-corejs2 fixed: 8.0.0-alpha.17
npm install @babel/runtime-corejs2@8.0.0-alpha.17
@babel/runtime-corejs3 fixed: 8.0.0-alpha.17
npm install @babel/runtime-corejs3@8.0.0-alpha.17
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

npm ls @babel/helpers

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2025-27789, inspect your project dependencies using npm:

npm ls @babel/helpers

Analyze the terminal output to locate any version of @babel/helpers in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 7.26.10), your application is affected.

Note: The npm ls @babel/helpers command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-1333: Inefficient Regular Expression Complexity, where the product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential. In @babel/helpers, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact When using Babel to compile [regular expression named capturing groups](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Named_capturing_group), 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: - You use Babel to compile [regular expression named capturing groups](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Named_capturing_group) - You use the `.replace` method on a regular expression that contains named capturing groups - **Your code uses untrusted strings as the second argument of `.replace`** If you are using `@babel/preset-env` with the [`targets`](https://babeljs.io/docs/options#targets) option, the transform that injects the vulnerable code is automatically enabled if: - you use [_duplicated_ named capturing groups](https://github.com/tc39/proposal-duplicate-named-capturing-groups), and target any browser older than Chrome/Edge 126, Opera 112, Firefox 129, Safari 17.4, or Node.js 23 - you use any [named capturing groups](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Named_capturing_group), and target any browser older than Chrome 64, Opera 71, Edge 79, Firefox 78, Safari 11.1, or Node.js 10 You can verify what transforms `@babel/preset-env` is using by enabling the [`debug` option](https://babeljs.io/docs/babel-preset-env#debug). ### Patches 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. ### Workarounds 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). ### References This vulnerability was reported and fixed in https://github.com/babel/babel/pull/17173.

CVE-2025-27789 Affected @babel/helpers Versions

8 component(s)
Fixed Versions:
7.26.108.0.0-alpha.17
Product / Package Ecosystem Affected Versions Fixed Version
@babel/helpers
npm
< 7.26.10
7.26.10
@babel/runtime
npm
< 7.26.10
7.26.10
@babel/runtime-corejs2
npm
< 7.26.10
7.26.10
@babel/runtime-corejs3
npm
< 7.26.10
7.26.10
@babel/helpers
npm
≥ 8.0.0-alpha.0
< 8.0.0-alpha.17
8.0.0-alpha.17
@babel/runtime
npm
≥ 8.0.0-alpha.0
< 8.0.0-alpha.17
8.0.0-alpha.17
@babel/runtime-corejs2
npm
≥ 8.0.0-alpha.0
< 8.0.0-alpha.17
8.0.0-alpha.17
@babel/runtime-corejs3
npm
≥ 8.0.0-alpha.0
< 8.0.0-alpha.17
8.0.0-alpha.17

References

Frequently Asked Questions

What is CVE-2025-27789?
CVE-2025-27789 is a security vulnerability in @babel/helpers involving Babel has inefficient RegExp complexity in generated code with .replace when transpiling named capturing groups under CWE-1333: Inefficient Regular Expression Complexity.
Which @babel/helpers versions are affected?
Affected versions include releases prior to 7.26.10, 8.0.0-alpha.17 across affected packages: @babel/helpers, @babel/runtime, @babel/runtime-corejs2, @babel/runtime-corejs3.
What version fixes CVE-2025-27789?
Upgrading to 7.26.10, 8.0.0-alpha.17 (or the latest patched release for your respective branch) resolves the vulnerability.
Is @babel/helpers affected?
Yes, @babel/helpers is affected in releases prior to 7.26.10, 8.0.0-alpha.17. Upgrade your dependency to 7.26.10, 8.0.0-alpha.17 or later.
Is @babel/runtime affected?
Yes, @babel/runtime is affected in releases prior to 7.26.10, 8.0.0-alpha.17. Upgrade your dependency to 7.26.10, 8.0.0-alpha.17 or later.
What is the CVSS score of CVE-2025-27789?
CVE-2025-27789 has a CVSS v3.1 base score of 6.2 (MODERATE) with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2025-27789?
CVE-2025-27789 is classified under CWE-1333: Inefficient Regular Expression Complexity (The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.).
How can I check npm dependencies for CVE-2025-27789?
Run the dependency tree command: 'npm ls @babel/helpers'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
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  "schema_version" : "1.4.0",
  "id" : "GHSA-968p-4wvh-cqc8",
  "modified" : "2025-04-16T15:39:50Z",
  "published" : "2025-03-11T20:30:18Z",
  "aliases" : [ "CVE-2025-27789" ],
  "summary" : "Babel has inefficient RegExp complexity in generated code with .replace when transpiling named capturing groups",
  "details" : "### Impact\n\nWhen using Babel to compile [regular expression named capturing groups](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Named_capturing_group), 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`).\n\nYour generated code is vulnerable if _all_ the following conditions are true:\n- You use Babel to compile [regular expression named capturing groups](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Named_capturing_group)\n- You use the `.replace` method on a regular expression that contains named capturing groups\n- **Your code uses untrusted strings as the second argument of `.replace`**\n\nIf you are using `@babel/preset-env` with the [`targets`](https://babeljs.io/docs/options#targets) option, the transform that injects the vulnerable code is automatically enabled if:\n- you use [_duplicated_ named capturing groups](https://github.com/tc39/proposal-duplicate-named-capturing-groups), and target any browser older than Chrome/Edge 126, Opera 112, Firefox 129, Safari 17.4, or Node.js 23\n- you use any [named capturing groups](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Named_capturing_group), and target any browser older than Chrome 64, Opera 71, Edge 79, Firefox 78, Safari 11.1, or Node.js 10\n\nYou can verify what transforms `@babel/preset-env` is using by enabling the [`debug` option](https://babeljs.io/docs/babel-preset-env#debug).\n\n\n### Patches\n\nThis 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.\n\nPlease note that just updating your Babel dependencies is not enough: you will also need to re-compile your code.\n\n### Workarounds\n\nIf 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).\n\n### References\n\nThis vulnerability was reported and fixed in https://github.com/babel/babel/pull/17173.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
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    "type" : "ADVISORY",
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}