{"id":"CVE-2026-100721","published":"2026-09-27T02:17:17.547","lastModified":"2026-09-28T17:17:46.057","description":"vm2 before 3.12.2 contains an authorization bypass in the NodeVM external-module resolver. When an embedder configures `require.external` with a custom resolver (and `context: 'host'`), `LegacyResolver.customResolve` in lib/resolver-compat.js records the resolved module directory in `this.externals` as `new RegExp('^' + escapeRegExp(resolvedPath))`, without requiring a path separator or end-of-string boundary. Untrusted guest code can therefore require the allowlisted module (e.g. `foo`) and then require the absolute path of a non-allowlisted sibling whose path merely shares the resolved prefix (e.g. `.../node_modules/foo2/index.js`); the sibling passes `isPathAllowedForModule` and is loaded through `hostRequire`, so its top-level code runs in the host process before the exports are wrapped with `vm.readonly`, resulting in a sandbox escape and arbitrary code execution in the host context.","cvssScore":9,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H","cwes":["CWE-863"],"vendors":[],"products":[],"references":[{"url":"https://github.com/patriksimek/vm2/commit/6ac3916da84e060c403e407b6b6318fcc66b0e72","tags":[]},{"url":"https://github.com/patriksimek/vm2/commit/91034466bfb7f56b95fd48083ec6ca36d058f164","tags":[]},{"url":"https://github.com/patriksimek/vm2/commit/ab4ee7d803e8c80155e9eb3672226bddbca4aa9c","tags":[]},{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-5h3f-q97h-ccvc","tags":[]},{"url":"https://www.vulncheck.com/advisories/vm2-before-3.12.2-authorization-bypass-via-custom-resolver","tags":[]}],"exploitRefs":[{"url":"https://github.com/patriksimek/vm2/commit/6ac3916da84e060c403e407b6b6318fcc66b0e72","tags":[]},{"url":"https://github.com/patriksimek/vm2/commit/91034466bfb7f56b95fd48083ec6ca36d058f164","tags":[]},{"url":"https://github.com/patriksimek/vm2/commit/ab4ee7d803e8c80155e9eb3672226bddbca4aa9c","tags":[]},{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-5h3f-q97h-ccvc","tags":[]}],"hasPoc":true,"ai":{"summary":"The flaw allows untrusted guest code to bypass authorization and execute arbitrary code in the host process, posing a critical risk.","exploitability":"Exploitation requires embedding the affected version and configuring a custom resolver, making it moderately complex but feasible.","blast_radius":"If exploited, this could lead to full control over the host system, with potential impacts ranging from data theft to complete system compromise.","remediation":"Upgrade to vm2 version 3.12.2 or later.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["rce","auth-bypass","nodejs","vm","critical"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-09-28T08:54:30.107Z"}}