CVE-2026-100721

Name of the Vulnerable Software and Affected Versions vm2 versions prior to 3.12.2

Description An authorization bypass exists in the NodeVM external-module resolver. When an embedder configures require.external with a custom resolver and context: 'host', the LegacyResolver.customResolve function in lib/resolver-compat.js records the resolved module directory in this.externals using a regular expression that lacks a path separator or end-of-string boundary. This allows untrusted guest code to require an allowlisted module and subsequently require the absolute path of a non-allowlisted sibling module that shares the same resolved prefix. Because the sibling passes isPathAllowedForModule, it is loaded through hostRequire, allowing its top-level code to execute in the host process before exports are wrapped with vm.readonly. This leads to a sandbox escape and arbitrary code execution in the host context.

Recommendations Update to version 3.12.2 or later.