{
  "cveId": "CVE-2021-34527",
  "url": "https://patchblox.com/security/cve/CVE-2021-34527",
  "summary": "CVE-2021-34527 is fixed in 38 products on 1 platform, first by KB5004954, released July 2, 2021. It is being exploited: CISA added it to the Known Exploited Vulnerabilities catalog on November 3, 2021, with known ransomware use. Patch Radar priority: Patch now.",
  "title": "Windows Print Spooler Remote Code Execution Vulnerability",
  "description": "\u003Cp\u003EA remote code execution vulnerability exists when the Windows Print Spooler service improperly performs privileged file operations. An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.\u003C/p\u003E\n\u003Cp\u003EUPDATE July 7, 2021: The security update for Windows Server 2012, Windows Server 2016 and Windows 10, Version 1607 have been released. Please see the Security Updates table for the applicable update for your system. We recommend that you install these updates immediately. If you are unable to install these updates, see the FAQ and Workaround sections in this CVE for information on how to help protect your system from this vulnerability.\u003C/p\u003E\n\u003Cp\u003EIn addition to installing the updates, in order to secure your system, you must confirm that the following registry settings are set to 0 (zero) or are not defined (\u003Cstrong\u003ENote\u003C/strong\u003E: These registry keys do not exist by default, and therefore are already at the secure setting.), also that your Group Policy setting are correct (see FAQ):\u003C/p\u003E\n\u003Cul\u003E\n\u003Cli\u003EHKEY_LOCAL_MACHINE\\SOFTWARE\\Policies\\Microsoft\\Windows NT\\Printers\\PointAndPrint\u003C/li\u003E\n\u003Cli\u003ENoWarningNoElevationOnInstall = 0 (DWORD) or not defined (default setting)\u003C/li\u003E\n\u003Cli\u003EUpdatePromptSettings = 0 (DWORD) or not defined (default setting)\u003C/li\u003E\n\u003C/ul\u003E\n\u003Cp\u003E\u003Cstrong\u003EHaving NoWarningNoElevationOnInstall set to 1 makes your system vulnerable by design.\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EUPDATE July 6, 2021: Microsoft has completed the investigation and has released security updates to address this vulnerability. Please see the Security Updates table for the applicable update for your system. We recommend that you install these updates immediately. If you are unable to install these updates, see the FAQ and Workaround sections in this CVE for information on how to help protect your system from this vulnerability. See also \u003Ca href=\u0022https://support.microsoft.com/topic/31b91c02-05bc-4ada-a7ea-183b129578a7\u0022\u003EKB5005010: Restricting installation of new printer drivers after applying the July 6, 2021 updates\u003C/a\u003E.\u003C/p\u003E\n\u003Cp\u003ENote that the security updates released on and after July 6, 2021 contain protections for CVE-2021-1675 and the additional remote code execution exploit in the Windows Print Spooler service known as \u201CPrintNightmare\u201D, documented in CVE-2021-34527.\u003C/p\u003E",
  "published": "2021-07-02T12:00:00Z",
  "severity": "Critical",
  "cvss": 8.8,
  "epss": 0.99792,
  "epssPercentile": 0.99956,
  "priority": "Patch now",
  "priorityTier": 1,
  "exploited": true,
  "vendorExploited": true,
  "disclosed": true,
  "exploitabilityAssessment": "Exploitation Detected",
  "kev": {
    "added": "2021-11-03T00:00:00Z",
    "due": "2022-05-03T00:00:00Z",
    "ransomware": true,
    "requiredAction": "Apply updates per vendor instructions."
  },
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34527",
  "fixes": [
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 1607 for 32-bit Systems",
      "fixedVersion": "14393.4470",
      "fix": "KB5004948",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004948",
      "released": "2021-07-07T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 1607 for x64-based Systems",
      "fixedVersion": "14393.4470",
      "fix": "KB5004948",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004948",
      "released": "2021-07-07T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 1809 for 32-bit Systems",
      "fixedVersion": "17763.2029",
      "fix": "KB5004947",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004947",
      "released": "2021-07-06T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 1809 for ARM64-based Systems",
      "fixedVersion": "17763.2029",
      "fix": "KB5004947",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004947",
      "released": "2021-07-06T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 1809 for x64-based Systems",
      "fixedVersion": "17763.2029",
      "fix": "KB5004947",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004947",
      "released": "2021-07-06T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 20H2 for 32-bit Systems",
      "fixedVersion": "",
      "fix": "KB5004945",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004945",
      "released": "2021-07-06T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 20H2 for ARM64-based Systems",
      "fixedVersion": "",
      "fix": "KB5004945",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004945",
      "released": "2021-07-06T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 20H2 for x64-based Systems",
      "fixedVersion": "",
      "fix": "KB5004945",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004945",
      "released": "2021-07-06T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 21H2 for 32-bit Systems",
      "fixedVersion": "",
      "fix": "KB5008212",
      "url": "https://patchblox.com/security/fix/microsoft/kb5008212",
      "released": "2021-12-14T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 21H2 for ARM64-based Systems",
      "fixedVersion": "",
      "fix": "KB5008212",
      "url": "https://patchblox.com/security/fix/microsoft/kb5008212",
      "released": "2021-12-14T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 21H2 for x64-based Systems",
      "fixedVersion": "",
      "fix": "KB5008212",
      "url": "https://patchblox.com/security/fix/microsoft/kb5008212",
      "released": "2021-12-14T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 22H2 for 32-bit Systems",
      "fixedVersion": "",
      "fix": "KB5019959",
      "url": "https://patchblox.com/security/fix/microsoft/kb5019959",
      "released": "2022-11-08T00:00:00Z"
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    {
      "platform": "microsoft",
      "product": "Windows 10 Version 22H2 for ARM64-based Systems",
      "fixedVersion": "",
      "fix": "KB5019959",
      "url": "https://patchblox.com/security/fix/microsoft/kb5019959",
      "released": "2022-11-08T00:00:00Z"
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    {
      "platform": "microsoft",
      "product": "Windows 10 Version 22H2 for x64-based Systems",
      "fixedVersion": "",
      "fix": "KB5019959",
      "url": "https://patchblox.com/security/fix/microsoft/kb5019959",
      "released": "2022-11-08T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 for 32-bit Systems",
      "fixedVersion": "10240.18969",
      "fix": "KB5004950",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004950",
      "released": "2021-07-06T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 for x64-based Systems",
      "fixedVersion": "10240.18969",
      "fix": "KB5004950",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004950",
      "released": "2021-07-06T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 11 Version 22H2 for ARM64-based Systems",
      "fixedVersion": "22621.674",
      "fix": "KB5018427",
      "url": "https://patchblox.com/security/fix/microsoft/kb5018427",
      "released": "2022-10-11T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 11 Version 22H2 for x64-based Systems",
      "fixedVersion": "22621.674",
      "fix": "KB5018427",
      "url": "https://patchblox.com/security/fix/microsoft/kb5018427",
      "released": "2022-10-11T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 11 version 21H2 for ARM64-based Systems",
      "fixedVersion": "22000.318",
      "fix": "KB5007215",
      "url": "https://patchblox.com/security/fix/microsoft/kb5007215",
      "released": "2021-11-09T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 11 version 21H2 for x64-based Systems",
      "fixedVersion": "22000.318",
      "fix": "KB5007215",
      "url": "https://patchblox.com/security/fix/microsoft/kb5007215",
      "released": "2021-11-09T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows RT 8.1",
      "fixedVersion": "",
      "fix": "KB5004954",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004954",
      "released": "2021-07-02T12:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2008 R2 for x64-based Systems Service Pack 1",
      "fixedVersion": "",
      "fix": "KB5004951",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004951",
      "released": "2021-07-02T12:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2008 R2 for x64-based Systems Service Pack 1",
      "fixedVersion": "",
      "fix": "KB5004953",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004953",
      "released": "2021-07-02T12:00:00Z"
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    {
      "platform": "microsoft",
      "product": "Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)",
      "fixedVersion": "",
      "fix": "KB5004951",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004951",
      "released": "2021-07-02T12:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)",
      "fixedVersion": "",
      "fix": "KB5004953",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004953",
      "released": "2021-07-02T12:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2008 for 32-bit Systems Service Pack 2",
      "fixedVersion": "",
      "fix": "KB5004955",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004955",
      "released": "2021-07-02T12:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2008 for 32-bit Systems Service Pack 2",
      "fixedVersion": "",
      "fix": "KB5004959",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004959",
      "released": "2021-07-02T12:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)",
      "fixedVersion": "",
      "fix": "KB5004955",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004955",
      "released": "2021-07-02T12:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)",
      "fixedVersion": "",
      "fix": "KB5004959",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004959",
      "released": "2021-07-02T12:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2008 for x64-based Systems Service Pack 2",
      "fixedVersion": "",
      "fix": "KB5004955",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004955",
      "released": "2021-07-02T12:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2008 for x64-based Systems Service Pack 2",
      "fixedVersion": "",
      "fix": "KB5004959",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004959",
      "released": "2021-07-02T12:00:00Z"
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    {
      "platform": "microsoft",
      "product": "Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)",
      "fixedVersion": "",
      "fix": "KB5004955",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004955",
      "released": "2021-07-02T12:00:00Z"
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    {
      "platform": "microsoft",
      "product": "Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)",
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      "url": "https://patchblox.com/security/fix/microsoft/kb5004959",
      "released": "2021-07-02T12:00:00Z"
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      "platform": "microsoft",
      "product": "Windows Server 2012",
      "fixedVersion": "",
      "fix": "KB5004960",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004960",
      "released": "2021-07-02T12:00:00Z"
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    {
      "platform": "microsoft",
      "product": "Windows Server 2012",
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      "released": "2021-07-02T12:00:00Z"
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      "platform": "microsoft",
      "product": "Windows Server 2012 (Server Core installation)",
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      "url": "https://patchblox.com/security/fix/microsoft/kb5004956",
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    {
      "platform": "microsoft",
      "product": "Windows Server 2012 R2",
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      "url": "https://patchblox.com/security/fix/microsoft/kb5004958",
      "released": "2021-07-02T12:00:00Z"
    },
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      "platform": "microsoft",
      "product": "Windows Server 2012 R2",
      "fixedVersion": "",
      "fix": "KB5004954",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004954",
      "released": "2021-07-02T12:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2012 R2 (Server Core installation)",
      "fixedVersion": "",
      "fix": "KB5004958",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004958",
      "released": "2021-07-02T12:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2012 R2 (Server Core installation)",
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      "released": "2021-07-02T12:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2016",
      "fixedVersion": "14393.4470",
      "fix": "KB5004948",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004948",
      "released": "2021-07-07T00:00:00Z"
    },
    {
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      "released": "2021-07-07T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2019",
      "fixedVersion": "17763.2029",
      "fix": "KB5004947",
      "url": "https://patchblox.com/security/fix/microsoft/kb5004947",
      "released": "2021-07-06T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2019 (Server Core installation)",
      "fixedVersion": "17763.2029",
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      "released": "2021-07-06T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2022",
      "fixedVersion": "20348.230",
      "fix": "KB5005575",
      "url": "https://patchblox.com/security/fix/microsoft/kb5005575",
      "released": "2021-09-14T00:00:00Z"
    },
    {
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      "product": "Windows Server 2022 (Server Core installation)",
      "fixedVersion": "20348.230",
      "fix": "KB5005575",
      "url": "https://patchblox.com/security/fix/microsoft/kb5005575",
      "released": "2021-09-14T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server, version 20H2 (Server Core Installation)",
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      "url": "https://patchblox.com/security/fix/microsoft/kb5004945",
      "released": "2021-07-06T00:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}