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

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.5%, percentile 44: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 44% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.
• Only applies if your dependency tree includes @babel/traverse (npm) < 7.23.2, fixed in 7.23.2; @babel/traverse (npm) >= 8.0.0-alpha.0, < 8.0.0-alpha.4, fixed in 8.0.0-alpha.4; babel-traverse (npm) < 7.23.2, no fixed version listed. Check your lockfile, including transitive dependencies.

What it is

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.

From the GitHub advisory

Impact

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 - 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.

Weakness type: CWE-184, CWE-697.

Product: @babel/traverse (npm) · Assigned by: GitHub_M · Published: 2023-10-12

Affected and fixed versions

Severity scores

• Attack vector: local access needed
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.53% probability of exploitation activity in the next 30 days; percentile 44.

Timeline

• 2023-10-12 — CVE record published by GitHub_M
• 2023-10-16 — GitHub-reviewed advisory GHSA-67hx-6x53-jw92 published (critical)
• 2025-02-13 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-67hx-6x53-jw92 github.com
2. CVE.org record CVE-2023-45133 cve.org
3. NVD entry CVE-2023-45133 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com
4. github.com github.com
5. github.com github.com
6. debian.org debian.org
7. lists.debian.org lists.debian.org
8. babeljs.io babeljs.io

Critical npm advisories · Today’s Security Digest