vm2 before 3.12.2 Authorization Bypass via Custom Resolver

{
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "cveMetadata": {
    "cveId": "CVE-2026-100721",
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "dateUpdated": "2026-09-27T01:28:28.596Z",
    "dateReserved": "2026-09-26T02:40:56.226Z",
    "datePublished": "2026-09-27T01:28:28.596Z",
    "state": "PUBLISHED"
  },
  "containers": {
    "cna": {
      "providerMetadata": {
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck",
        "dateUpdated": "2026-09-27T01:28:28.596Z"
      },
      "datePublic": "2026-09-08T00:00:00.000Z",
      "title": "vm2 before 3.12.2 Authorization Bypass via Custom Resolver",
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "affected": [
        {
          "vendor": "patriksimek",
          "product": "vm2",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "3.12.2"
            },
            {
              "version": "3.12.2",
              "status": "unaffected",
              "versionType": "semver"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "lang": "en",
              "description": "Incorrect Authorization",
              "cweId": "CWE-863",
              "type": "CWE"
            }
          ]
        }
      ],
      "references": [
        {
          "url": "https://github.com/patriksimek/vm2/security/advisories/GHSA-5h3f-q97h-ccvc",
          "name": "GitHub Security Advisory (GHSA-5h3f-q97h-ccvc)",
          "tags": [
            "vendor-advisory"
          ]
        },
        {
          "url": "https://github.com/patriksimek/vm2/commit/6ac3916da84e060c403e407b6b6318fcc66b0e72",
          "name": "Patch Commit",
          "tags": [
            "patch"
          ]
        },
        {
          "url": "https://github.com/patriksimek/vm2/commit/ab4ee7d803e8c80155e9eb3672226bddbca4aa9c",
          "name": "Patch Commit",
          "tags": [
            "patch"
          ]
        },
        {
          "url": "https://github.com/patriksimek/vm2/commit/91034466bfb7f56b95fd48083ec6ca36d058f164",
          "name": "Patch Commit",
          "tags": [
            "patch"
          ]
        },
        {
          "url": "https://www.vulncheck.com/advisories/vm2-before-3.12.2-authorization-bypass-via-custom-resolver",
          "name": "VulnCheck Advisory: vm2 before 3.12.2 Authorization Bypass via Custom Resolver",
          "tags": [
            "third-party-advisory"
          ]
        }
      ],
      "metrics": [
        {
          "format": "CVSS"
        },
        {
          "format": "CVSS",
          "cvssV3_1": {
            "version": "3.1",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H",
            "attackVector": "NETWORK",
            "attackComplexity": "HIGH",
            "privilegesRequired": "NONE",
            "userInteraction": "NONE",
            "scope": "CHANGED",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "availabilityImpact": "HIGH",
            "baseScore": 9,
            "baseSeverity": "CRITICAL"
          }
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "rexpository",
          "type": "reporter"
        }
      ]
    }
  }
}