{"id":"CVE-2026-100721","revision":"63d0ef9204d8450b87aa990de3c94d0d","records":[{"revision":"63d0ef9204d8450b87aa990de3c94d0d","observedAt":"2026-10-25T04:17:26.915+00:00","statement":{"source":"nvd","id":"CVE-2026-100721","aliases":[],"title":"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.…","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.","state":0,"publishedAt":"2026-09-27T02:17:17.547+00:00","modifiedAt":"2026-09-28T17:17:46.057+00:00","affected":[],"metrics":[{"system":"CVSS 4.0 · disclosure@vulncheck.com · Secondary","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","score":9.5,"severity":"CRITICAL"},{"system":"CVSS 3.1 · disclosure@vulncheck.com · Secondary","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H","score":9,"severity":"CRITICAL"}],"references":["https://github.com/patriksimek/vm2/commit/6ac3916da84e060c403e407b6b6318fcc66b0e72","https://github.com/patriksimek/vm2/commit/91034466bfb7f56b95fd48083ec6ca36d058f164","https://github.com/patriksimek/vm2/commit/ab4ee7d803e8c80155e9eb3672226bddbca4aa9c","https://github.com/patriksimek/vm2/security/advisories/GHSA-5h3f-q97h-ccvc","https://www.vulncheck.com/advisories/vm2-before-3.12.2-authorization-bypass-via-custom-resolver"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-100721","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Deferred","weaknesses":["CWE-863"],"productCriteria":[],"sourceDates":{"published":"2026-09-27T02:17:17.547","lastModified":"2026-09-28T17:17:46.057"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-100721","identifiers":["CVE-2026-100721"]},"retained":false,"historicalAffected":[]}],"coverage":[]}