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Arbitrary Code Execution in Babel @babel/traverse during compilation

IdentifiersCVE-2023-45133CWE-184· Incomplete List of Disallowed Inputs

CVE-2023-45133 is an arbitrary code execution vulnerability in @babel/traverse prior to 7.23.2 and 8.0.0-alpha.4, and in all versions of babel-traverse. When Babel compiles attacker-crafted JavaScript and a plugin invokes the internal path.evaluate() or path.evaluateTruthy() methods on that input, the vulnerable evaluation path can result in code execution during the compilation/build process. Known affected plugins include @babel/plugin-transform-runtime, @babel/preset-env when useBuiltIns is enabled, and polyfill-provider plugins built on @babel/helper-define-polyfill-provider, including babel-plugin-polyfill-corejs2, babel-plugin-polyfill-corejs3, babel-plugin-polyfill-es-shims, and babel-plugin-polyfill-regenerator. The issue does not affect users who only compile trusted code.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows arbitrary code execution in the context of the system or process performing the Babel compilation. In practice, this can compromise CI/CD runners, developer workstations, build servers, or other environments that process untrusted source code, with potential follow-on impact including theft or modification of source code and build artifacts, access to secrets available to the build process, and broader compromise of the build environment.

Mitigation

If you can’t patch tonight, do this now.

Do not use vulnerable Babel toolchains to compile untrusted or externally supplied code. If only trusted code is compiled, exposure is substantially reduced per the advisory. As an interim measure, ensure affected plugins are upgraded to versions that do not trigger the vulnerable evaluation path, remove pinned vulnerable @babel/traverse versions from lockfiles, and reinstall dependencies so a fixed version is resolved. Restrict build execution environments and limit available secrets to reduce blast radius if exploitation occurs.

Remediation

Patch, then assume compromise.

Upgrade @babel/traverse to 7.23.2 or later, or to 8.0.0-alpha.4 or later. Where dependency resolution is indirect, upgrade @babel/core to a version that pulls a fixed @babel/traverse. Babel 6 (babel-traverse) is end-of-life and does not receive a security fix; affected users should migrate off Babel 6. If upgrading @babel/traverse is not immediately possible, upgrade affected packages to versions that avoid the vulnerable code path: @babel/plugin-transform-runtime 7.23.2, @babel/preset-env 7.23.2, @babel/helper-define-polyfill-provider 0.4.3, babel-plugin-polyfill-corejs2 0.4.6, babel-plugin-polyfill-corejs3 0.8.5, babel-plugin-polyfill-es-shims 0.10.0, and babel-plugin-polyfill-regenerator 0.5.3.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
BabeljsBabelapplication
BabeljsBabel-Helper-Define-Polyfill-Providerapplication
BabeljsBabel-Plugin-Polyfill-Corejs2application
BabeljsBabel-Plugin-Polyfill-Corejs3application
BabeljsBabel-Plugin-Polyfill-Es-Shimsapplication
BabeljsBabel-Plugin-Polyfill-Regeneratorapplication
BabeljsBabel-Plugin-Transform-Runtimeapplication
BabeljsBabel-Preset-Envapplication
DebianDebian Linuxoperating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

2 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

The version that knows your environment.

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1

Community discussion across Reddit, Mastodon, and other social sources.