CVE-2023-45133: Babel vulnerable to arbitrary code execution when compiling specifically crafted malicious code

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-10-12 · updated 2026-06-17
Weakness: CWE-184

Description

Babel is a compiler for writingJavaScript. In `@babel/traverse` prior to versions 7.23.2 and 8.0.0-alpha.4 and all versions of `babel-traverse`, using Babel to compile code that was specifically crafted by an attacker can lead to arbitrary code execution during compilation, when using plugins that rely on the `path.evaluate()`or `path.evaluateTruthy()` internal Babel methods. Known affected plugins are `@babel/plugin-transform-runtime`; `@babel/preset-env` when using its `useBuiltIns` option; and any "polyfill provider" plugin that depends on `@babel/helper-define-polyfill-provider`, such as `babel-plugin-polyfill-corejs3`, `babel-plugin-polyfill-corejs2`, `babel-plugin-polyfill-es-shims`, `babel-plugin-polyfill-regenerator`. No other plugins under the `@babel/` namespace are impacted, but third-party plugins might be. Users that only compile trusted code are not impacted. The vulnerability has been fixed in `@babel/traverse@7.23.2` and `@babel/traverse@8.0.0-alpha.4`. Those who cannot upgrade `@babel/traverse` and are using one of the affected packages mentioned above should upgrade them to their latest version to avoid triggering the vulnerable code path in affected `@babel/traverse` versions: `@babel/plugin-transform-runtime` v7.23.2, `@babel/preset-env` v7.23.2, `@babel/helper-define-polyfill-provider` v0.4.3, `babel-plugin-polyfill-corejs2` v0.4.6, `babel-plugin-polyfill-corejs3` v0.8.5, `babel-plugin-polyfill-es-shims` v0.10.0, `babel-plugin-polyfill-regenerator` v0.5.3.

Affected products

Babeljs Babel: before 7.23.2; 8.0.0-alpha.0, 8.0.0-alpha.1, 8.0.0-alpha.2, 8.0.0-alpha.3 — fixed in 7.23.2
Babeljs Babel-Helper-Define-Polyfill-Provider: before 0.4.3 — fixed in 0.4.3
Babeljs Babel-Plugin-Polyfill-Corejs2: before 0.4.6 — fixed in 0.4.6
Babeljs Babel-Plugin-Polyfill-Corejs3: before 0.8.5 — fixed in 0.8.5
Babeljs Babel-Plugin-Polyfill-Es-Shims: before 0.10.0 — fixed in 0.10.0
Babeljs Babel-Plugin-Polyfill-Regenerator: before 0.5.3 — fixed in 0.5.3
Babeljs Babel-Plugin-Transform-Runtime: before 7.23.2 — fixed in 7.23.2
Babeljs Babel-Preset-Env: before 7.23.2 — fixed in 7.23.2
Debian Linux: 10.0, 11.0, 12.0
Npm @Babel/Traverse: before 7.23.2; from 8.0.0-alpha.0 before 8.0.0-alpha.4 — fixed in 7.23.2, 8.0.0-alpha.4
Npm Babel-Traverse: all versions

How to fix

Upgrade to a fixed version: Babeljs Babel 7.23.2; Babeljs Babel-Helper-Define-Polyfill-Provider 0.4.3; Babeljs Babel-Plugin-Polyfill-Corejs2 0.4.6; Babeljs Babel-Plugin-Polyfill-Corejs3 0.8.5; Babeljs Babel-Plugin-Polyfill-Es-Shims 0.10.0; Babeljs Babel-Plugin-Polyfill-Regenerator 0.5.3; Babeljs Babel-Plugin-Transform-Runtime 7.23.2; Babeljs Babel-Preset-Env 7.23.2; Npm @Babel/Traverse 7.23.2, 8.0.0-alpha.4. Check the vendor advisory for mitigations.

References

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