vm2 before 3.12.2 Memory Disclosure via zlib Buffer Pool

{
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "cveMetadata": {
    "cveId": "CVE-2026-100723",
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "dateUpdated": "2026-09-27T01:28:30.027Z",
    "dateReserved": "2026-09-26T02:40:56.226Z",
    "datePublished": "2026-09-27T01:28:30.027Z",
    "state": "PUBLISHED"
  },
  "containers": {
    "cna": {
      "providerMetadata": {
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck",
        "dateUpdated": "2026-09-27T01:28:30.027Z"
      },
      "datePublic": "2026-09-08T00:00:00.000Z",
      "title": "vm2 before 3.12.2 Memory Disclosure via zlib Buffer Pool",
      "descriptions": [
        {
          "lang": "en",
          "value": "vm2 before 3.12.2 does not apply its Buffer backing-store ownership invariant (byteOffset === 0 and buffer.byteLength === length) to Buffers returned from host builtin modules. When an application explicitly exposes Node's zlib module through NodeVM's builtin allowlist (require: { builtin: ['zlib'] }), zlib.deflateSync can return a Buffer backed by Node's shared small-buffer pool whose .buffer is the entire pool. Untrusted guest code can construct a full-width view of that ArrayBuffer (Buffer.from(result.buffer, 0, result.buffer.byteLength)) to read and modify bytes belonging to unrelated host buffers, disclosing and corrupting host-realm memory across the sandbox boundary."
        }
      ],
      "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": "Exposure of Sensitive Information to an Unauthorized Actor",
              "cweId": "CWE-200",
              "type": "CWE"
            }
          ]
        }
      ],
      "references": [
        {
          "url": "https://github.com/patriksimek/vm2/security/advisories/GHSA-489w-w794-jq94",
          "name": "GitHub Security Advisory (GHSA-489w-w794-jq94)",
          "tags": [
            "vendor-advisory"
          ]
        },
        {
          "url": "https://github.com/patriksimek/vm2/commit/4f2508abeb252aa86eb6761c78b3b000248fb089",
          "name": "Patch Commit",
          "tags": [
            "patch"
          ]
        },
        {
          "url": "https://github.com/patriksimek/vm2/commit/5214b02ef13b82497fcb917b45320dfd014ffd09",
          "name": "Patch Commit",
          "tags": [
            "patch"
          ]
        },
        {
          "url": "https://www.vulncheck.com/advisories/vm2-before-3.12.2-memory-disclosure-via-zlib-buffer-pool",
          "name": "VulnCheck Advisory: vm2 before 3.12.2 Memory Disclosure via zlib Buffer Pool",
          "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:L/A:N",
            "attackVector": "NETWORK",
            "attackComplexity": "HIGH",
            "privilegesRequired": "NONE",
            "userInteraction": "NONE",
            "scope": "CHANGED",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "LOW",
            "availabilityImpact": "NONE",
            "baseScore": 7.5,
            "baseSeverity": "HIGH"
          }
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "rexpository",
          "type": "reporter"
        }
      ]
    }
  }
}