{
  "id": "CVE-2021-33771",
  "url": "https://spydr.io/cve/CVE-2021-33771",
  "published": "2021-07-14T18:15:10.483Z",
  "modified": "2026-08-10T19:58:46.650Z",
  "score": 7.8,
  "severity": "high",
  "cvss_version": "3.1",
  "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
  "score_source": "microsoft.com",
  "epss": 0.10172,
  "epss_percentile": 0.95552,
  "exploited": true,
  "kev": {
    "added": "2021-11-03",
    "due": "2021-11-17",
    "action": "Apply updates per vendor instructions.",
    "ransomware": "Unknown",
    "name": "Microsoft Windows Kernel Privilege Escalation Vulnerability",
    "notes": "https://nvd.nist.gov/vuln/detail/CVE-2021-33771"
  },
  "ssvc_exploitation": "active",
  "vendors": [
    "Microsoft"
  ],
  "products": [
    "Microsoft Windows 10 Version 1507",
    "Microsoft Windows 10 Version 1607",
    "Microsoft Windows 10 Version 1809",
    "Microsoft Windows 10 Version 1909",
    "Microsoft Windows 10 Version 2004",
    "Microsoft Windows 10 Version 20H2",
    "Microsoft Windows 10 Version 21H1",
    "Microsoft Windows 8.1",
    "Microsoft Windows Server 2012 R2",
    "Microsoft Windows Server 2012 R2 (Server Core installation)",
    "Microsoft Windows Server 2016",
    "Microsoft Windows Server 2016 (Server Core installation)",
    "Microsoft Windows Server 2019",
    "Microsoft Windows Server 2019 (Server Core installation)",
    "Microsoft Windows Server version 2004",
    "Microsoft Windows Server version 20H2"
  ],
  "cwes": [],
  "description": "Windows Kernel Elevation of Privilege Vulnerability",
  "status": "Analyzed",
  "score_type": "Secondary",
  "scores": {
    "cvss_v40": null,
    "cvss_v31": 7.8,
    "cvss_v30": null
  },
  "references": [
    {
      "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-33771",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33771",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33771",
      "tags": [
        "US Government Resource"
      ]
    }
  ],
  "nvd_url": "https://nvd.nist.gov/vuln/detail/CVE-2021-33771",
  "covered_in": [],
  "attribution": [
    {
      "source": "NVD",
      "url": "https://nvd.nist.gov",
      "notice": "This product uses data from the NVD API but is not endorsed or certified by the NVD."
    },
    {
      "source": "CISA KEV",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "notice": "Known exploited vulnerabilities from the CISA KEV catalog."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss",
      "notice": "Exploit prediction scores from FIRST EPSS."
    }
  ]
}