{"id":"CVE-2026-100721","summary":"vm2 before 3.12.2 Authorization Bypass via Custom Resolver","details":"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.","aliases":["GHSA-5h3f-q97h-ccvc"],"modified":"2026-09-28T03:48:31.532515631Z","published":"2026-09-27T01:28:28.596Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/100xxx/CVE-2026-100721.json","cna_assigner":"VulnCheck","cwe_ids":["CWE-863"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/100xxx/CVE-2026-100721.json"},{"type":"ADVISORY","url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-5h3f-q97h-ccvc"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-100721"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/vm2-before-3.12.2-authorization-bypass-via-custom-resolver"},{"type":"FIX","url":"https://github.com/patriksimek/vm2/commit/6ac3916da84e060c403e407b6b6318fcc66b0e72"},{"type":"FIX","url":"https://github.com/patriksimek/vm2/commit/91034466bfb7f56b95fd48083ec6ca36d058f164"},{"type":"FIX","url":"https://github.com/patriksimek/vm2/commit/ab4ee7d803e8c80155e9eb3672226bddbca4aa9c"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/patriksimek/vm2","events":[{"introduced":"0"},{"fixed":"a0139cf6a7ad72a685420f53479a99fe385cf394"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"3.12.2"}],"source":"AFFECTED_FIELD"}}],"versions":["v3.12.1","v3.12.0","v3.11.8","v3.11.7","3.11.6","v3.11.5","v3.11.4","v3.11.3","v3.11.2","v3.11.1","v3.11.0","v3.10.5","v3.10.4","v3.10.3","v3.10.2","v3.10.1","v3.10.0","3.9.19","3.9.18","3.9.17","3.9.16","3.9.15","3.9.14","3.9.13","3.9.12","3.9.11","3.9.10","3.9.9","3.9.8","3.9.7","3.9.6","3.9.5","3.9.4","3.9.3","v3.9.2","v3.9.1","v3.9.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-100721.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"}]}