{"id":"CVE-2026-100721","title":"vm2 before 3.12.2 contains an authorization bypass in the NodeVM external-module resolver","summary":"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-comp…","severity":"critical","cvss":9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H","cwe":["CWE-863"],"vendor":"patriksimek","product":"vm2","affected":["vm2 < 3.12.2"],"published":"2026-09-27","updated":"2026-09-28","sourceUpdated":"2026-09-28T17:17:46.057","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-100721","references":[{"url":"https://github.com/patriksimek/vm2/commit/6ac3916da84e060c403e407b6b6318fcc66b0e72","label":"disclosure@vulncheck.com"},{"url":"https://github.com/patriksimek/vm2/commit/91034466bfb7f56b95fd48083ec6ca36d058f164","label":"disclosure@vulncheck.com"},{"url":"https://github.com/patriksimek/vm2/commit/ab4ee7d803e8c80155e9eb3672226bddbca4aa9c","label":"disclosure@vulncheck.com"},{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-5h3f-q97h-ccvc","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/vm2-before-3.12.2-authorization-bypass-via-custom-resolver","label":"disclosure@vulncheck.com"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-100721"},{"url":"https://github.com/patriksimek/vm2/commit/fb4977f6211da6cadffdf1f3a2017a826a21c51f"},{"url":"https://github.com/patriksimek/vm2/releases/tag/v3.12.2"},{"url":"https://github.com/advisories/GHSA-5h3f-q97h-ccvc"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100721.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-100721"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2541992"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-100721"},{"url":"https://access.redhat.com/errata/RHSA-2026:88200"}],"tags":["nvd","exploit-available","cve.org","ghsa","npm","csaf","vex","red-hat"],"exploits":{"github":1,"githubRepos":["https://github.com/murrez/CVE-2026-100721"],"checkedAt":"2026-10-27T16:52:20.325Z"},"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"total","timestamp":"2026-09-28T16:50:50.404410Z"},"ingestedAt":"2026-09-27T02:41:45.564Z","epss":0.00591,"epssPercentile":0.48058,"aliases":["GHSA-5h3f-q97h-ccvc"],"ecosystem":"npm","patched":["vm2 3.12.2"],"scores":{"nvd":9,"ghsa":10,"vendor":9},"slug":"CVE-2026-100721","body":"## Overview\n\nvm2 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-100721)\n\nAffected packages:\n\n- `vm2 <= 3.12.1`\n\nPatched in:\n\n- `vm2 3.12.2`\n\nSource: https://github.com/advisories/GHSA-5h3f-q97h-ccvc\n\n## Vendor advisories\n\n- **Red Hat VEX** · Critical · affected: Self-service automation portal 2 · no fix planned: Self-service automation portal 2 · updated 2026-10-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100721.json)\n- **RHSA-2026:88200** · Red Hat · fixed in: Red Hat Ansible Automation Platform 2.2 · released 2026-10-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:88200)","depth":"abyssal","depthScore":62,"depthScoreParts":{"impact":49.5,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":212044,"id":"CVE-2026-100721","ts":1790615857903,"field":"exploit_available","old":"false","new":"true"}]}