{
  "cveId": "CVE-2021-40444",
  "url": "https://patchblox.com/security/cve/CVE-2021-40444",
  "summary": "CVE-2021-40444 is fixed in 42 products on 1 platform, first by KB5005563, released July 13, 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": "Microsoft MSHTML Remote Code Execution Vulnerability",
  "description": "\u003Cp\u003EMicrosoft is investigating reports of a remote code execution vulnerability in MSHTML that affects Microsoft Windows. Microsoft is aware of targeted attacks that attempt to exploit this vulnerability by using specially-crafted Microsoft Office documents.\u003C/p\u003E\n\u003Cp\u003EAn attacker could craft a malicious ActiveX control to be used by a Microsoft Office document that hosts the browser rendering engine. The attacker would then have to convince the user to open the malicious document. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.\u003C/p\u003E\n\u003Cp\u003EMicrosoft Defender Antivirus and Microsoft Defender for Endpoint both provide detection and protections for the known vulnerability. Customers should keep antimalware products up to date. Customers who utilize automatic updates do not need to take additional action. Enterprise customers who manage updates should select the detection build 1.349.22.0 or newer and deploy it across their environments. Microsoft Defender for Endpoint alerts will be displayed as: \u201CSuspicious Cpl File Execution\u201D.\u003C/p\u003E\n\u003Cp\u003EUpon completion of this investigation, Microsoft will take the appropriate action to help protect our customers. This may include providing a security update through our monthly release process or providing an out-of-cycle security update, depending on customer needs.\u003C/p\u003E\n\u003Cp\u003EPlease see the \u003Cstrong\u003EMitigations\u003C/strong\u003E and \u003Cstrong\u003EWorkaround\u003C/strong\u003E sections for important information about steps you can take to protect your system from this vulnerability.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EUPDATE\u003C/strong\u003E September 14, 2021: Microsoft 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. Please see the FAQ for important information about which updates are applicable to your system.\u003C/p\u003E",
  "published": "2021-09-07T12:00:00Z",
  "severity": "Important",
  "cvss": 8.8,
  "epss": 0.9784,
  "epssPercentile": 0.99907,
  "priority": "Patch now",
  "priorityTier": 1,
  "exploited": true,
  "vendorExploited": true,
  "disclosed": true,
  "exploitabilityAssessment": "Exploitation Detected",
  "kev": {
    "added": "2021-11-03T00:00:00Z",
    "due": "2021-11-17T00:00:00Z",
    "ransomware": true,
    "requiredAction": "Apply updates per vendor instructions."
  },
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-40444",
  "fixes": [
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      "platform": "microsoft",
      "product": "Windows 10 Version 1607 for 32-bit Systems",
      "fixedVersion": "14393.4651",
      "fix": "KB5005573",
      "url": "https://patchblox.com/security/fix/microsoft/kb5005573",
      "released": "2021-09-14T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 1607 for x64-based Systems",
      "fixedVersion": "14393.4651",
      "fix": "KB5005573",
      "url": "https://patchblox.com/security/fix/microsoft/kb5005573",
      "released": "2021-09-14T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 1809 for 32-bit Systems",
      "fixedVersion": "17763.2183",
      "fix": "KB5005568",
      "url": "https://patchblox.com/security/fix/microsoft/kb5005568",
      "released": "2021-09-14T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 1809 for ARM64-based Systems",
      "fixedVersion": "17763.2183",
      "fix": "KB5005568",
      "url": "https://patchblox.com/security/fix/microsoft/kb5005568",
      "released": "2021-09-14T00:00:00Z"
    },
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      "platform": "microsoft",
      "product": "Windows 10 Version 1809 for x64-based Systems",
      "fixedVersion": "17763.2183",
      "fix": "KB5005568",
      "url": "https://patchblox.com/security/fix/microsoft/kb5005568",
      "released": "2021-09-14T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 1909 for 32-bit Systems",
      "fixedVersion": "18363.1801",
      "fix": "KB5005566",
      "url": "https://patchblox.com/security/fix/microsoft/kb5005566",
      "released": "2021-09-14T00:00:00Z"
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      "fix": "KB5005566",
      "url": "https://patchblox.com/security/fix/microsoft/kb5005566",
      "released": "2021-09-14T00:00:00Z"
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      "released": "2021-09-14T00:00:00Z"
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      "fix": "KB5005565",
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    {
      "platform": "microsoft",
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      "fixedVersion": "10240.19060",
      "fix": "KB5005569",
      "url": "https://patchblox.com/security/fix/microsoft/kb5005569",
      "released": "2021-09-14T00:00:00Z"
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      "platform": "microsoft",
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      "released": "2022-11-08T14:00:00Z"
    },
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      "url": "https://patchblox.com/security/fix/microsoft/kb5005627",
      "released": "2021-09-14T12:00:00Z"
    },
    {
      "platform": "microsoft",
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      "fixedVersion": "",
      "fix": "KB5005613",
      "url": "https://patchblox.com/security/fix/microsoft/kb5005613",
      "released": "2021-09-14T12:00:00Z"
    },
    {
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    },
    {
      "platform": "microsoft",
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      "url": "https://patchblox.com/security/fix/microsoft/kb5005627",
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      "platform": "microsoft",
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    {
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    {
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    },
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  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
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    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
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}