CVE-2023-45133 is a critical-severity (CVSS 9.3) CWE-184 vulnerability in @babel/traverse. A fix is available for @babel/traverse — see the affected versions and patch details below.
Babel vulnerable to arbitrary code execution when compiling specifically crafted malicious code
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-45133.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-45133 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@babel/traversenpmbabel-traversenpmDescription
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-envwhen using itsuseBuiltInsoption- Any "polyfill provider" plugin that depends on
@babel/helper-define-polyfill-provider, such asbabel-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.
Patches
The vulnerability has been fixed in @babel/[email protected].
Babel 6 does not receive security fixes anymore (see Babel's security policy), hence there is no patch planned for babel-traverse@6.
Workarounds
- Upgrade
@babel/traverseto v7.23.2 or higher. You can do this by deleting it from your package manager's lockfile and re-installing the dependencies.@babel/core>=7.23.2 will automatically pull in a non-vulnerable version. - If you cannot upgrade
@babel/traverseand are using one of the affected packages mentioned above, upgrade them to their latest version to avoid triggering the vulnerable code path in affected@babel/traverseversions:@babel/plugin-transform-runtimev7.23.2@babel/preset-envv7.23.2@babel/helper-define-polyfill-providerv0.4.3babel-plugin-polyfill-corejs2v0.4.6babel-plugin-polyfill-corejs3v0.8.5babel-plugin-polyfill-es-shimsv0.10.0babel-plugin-polyfill-regeneratorv0.5.3
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @babel/traverse | all versions | 7.23.2npm install @babel/traverse@7.23.2 |
| 📦npm | @babel/traverse | ≥ 8.0.0-alpha.0&&< 8.0.0-alpha.4 | 8.0.0-alpha.4npm install @babel/traverse@8.0.0-alpha.4 |
| 📦npm | babel-traverse | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @babel/traverse, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @babel/traverse to 7.23.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-45133 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-45133 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-45133. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-45133 in your dependencies?
O3 Security finds CVE-2023-45133 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.