CVE-2021-40444 (GCVE-0-2021-40444)
Vulnerability from cvelistv5 – Published: 2021-09-15 11:24 – Updated: 2026-08-10 15:10Title
Microsoft MSHTML Remote Code Execution Vulnerability
Summary
Microsoft 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.
An 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.
Microsoft 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: “Suspicious Cpl File Execution”.
Upon 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.
Please see the Mitigations and Workaround sections for important information about steps you can take to protect your system from this vulnerability.
UPDATE 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.
Severity
SSVC
Exploitation: active
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2021-09-08 00:00 UTC
CWE
- Remote Code Execution
- CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Assigner
References
6 references
| URL | Tags |
|---|---|
| https://msrc.microsoft.com/update-guide/vulnerabi… | vendor-advisorypatch |
| https://portal.msrc.microsoft.com/en-US/security-… | x_refsource_MISCx_transferred |
| http://packetstormsecurity.com/files/164210/Micro… | x_refsource_MISCx_transferred |
| http://packetstormsecurity.com/files/165214/Micro… | x_refsource_MISCx_transferred |
| http://packetstormsecurity.com/files/167317/Micro… | x_refsource_MISCx_transferred |
| https://www.cisa.gov/known-exploited-vulnerabilit… | government-resource |
Impacted products
26 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Microsoft | Windows 10 Version 1507 |
Affected:
10.0.10240.0 , < 10.0.10240.19060
(custom)
|
guessed | |
| Microsoft | Windows 10 Version 1607 |
Affected:
10.0.14393.0 , < 10.0.14393.4651
(custom)
|
guessed | |
| Microsoft | Windows 10 Version 1809 |
Affected:
10.0.17763.0 , < 10.0.17763.2183
(custom)
|
guessed | |
| Microsoft | Windows 10 Version 1809 |
Affected:
10.0.0 , < 10.0.17763.2183
(custom)
|
guessed | |
| Microsoft | Windows 10 Version 1909 |
Affected:
10.0.0 , < 10.0.18363.1801
(custom)
|
guessed | |
| Microsoft | Windows 10 Version 2004 |
Affected:
10.0.0 , < 10.0.19041.1237
(custom)
|
guessed | |
| Microsoft | Windows 10 Version 20H2 |
Affected:
10.0.0 , < 10.0.19042.1237
(custom)
|
guessed | |
| Microsoft | Windows 10 Version 21H1 |
Affected:
10.0.0 , < 10.0.19043.1237
(custom)
|
guessed | |
| Microsoft | Windows 7 |
Affected:
6.1.0 , < 6.1.7601.25712
(custom)
|
guessed | |
| Microsoft | Windows 7 Service Pack 1 |
Affected:
6.1.0 , < 6.1.7601.25712
(custom)
|
guessed | |
| Microsoft | Windows 8.1 |
Affected:
6.3.0 , < 6.3.9600.20120
(custom)
|
guessed | |
| Microsoft | Windows Server 2008 R2 Service Pack 1 |
Affected:
6.1.7601.0 , < 6.1.7601.25712
(custom)
|
guessed | |
| Microsoft | Windows Server 2008 R2 Service Pack 1 (Server Core installation) |
Affected:
6.1.7601.0 , < 6.1.7601.25712
(custom)
|
guessed | |
| Microsoft | Windows Server 2008 Service Pack 2 |
Affected:
6.0.6003.0 , < 6.0.6003.21218
(custom)
|
guessed | |
| Microsoft | Windows Server 2008 Service Pack 2 (Server Core installation) |
Affected:
6.0.6003.0 , < 6.0.6003.21218
(custom)
|
guessed | |
| Microsoft | Windows Server 2012 |
Affected:
6.2.9200.0 , < 6.2.9200.23462
(custom)
|
guessed | |
| Microsoft | Windows Server 2012 (Server Core installation) |
Affected:
6.2.9200.0 , < 6.2.9200.23462
(custom)
|
guessed | |
| Microsoft | Windows Server 2012 R2 |
Affected:
6.3.9600.0 , < 6.3.9600.20120
(custom)
|
guessed | |
| Microsoft | Windows Server 2012 R2 (Server Core installation) |
Affected:
6.3.9600.0 , < 6.3.9600.20120
(custom)
|
guessed | |
| Microsoft | Windows Server 2016 |
Affected:
10.0.14393.0 , < 10.0.14393.4651
(custom)
|
guessed | |
| Microsoft | Windows Server 2016 (Server Core installation) |
Affected:
10.0.14393.0 , < 10.0.14393.4651
(custom)
|
guessed | |
| Microsoft | Windows Server 2019 |
Affected:
10.0.17763.0 , < 10.0.17763.2183
(custom)
|
guessed | |
| Microsoft | Windows Server 2019 (Server Core installation) |
Affected:
10.0.17763.0 , < 10.0.17763.2183
(custom)
|
guessed | |
| Microsoft | Windows Server 2022 |
Affected:
10.0.20348.0 , < 10.0.20348.230
(custom)
|
guessed | |
| Microsoft | Windows Server version 2004 |
Affected:
10.0.0 , < 10.0.19041.1237
(custom)
|
guessed | |
| Microsoft | Windows Server version 20H2 |
Affected:
10.0.0 , < 10.0.19042.1237
(custom)
|
guessed |
Date Public
2021-09-07 14:00
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: c0b3741d-863c-48f6-baa7-727eb37b8306
Exploited: Yes
Timestamps
First Seen: 2021-11-03
Asserted: 2021-11-03
Scope
Notes: KEV entry: Microsoft MSHTML Remote Code Execution Vulnerability | Affected: Microsoft / MSHTML | Description: Microsoft MSHTML contains a unspecified vulnerability that allows for remote code execution. | Required action: Apply updates per vendor instructions. | Due date: 2021-11-17 | Known ransomware campaign use (KEV): Known | Notes (KEV): https://nvd.nist.gov/vuln/detail/CVE-2021-40444
Evidence
Type: Vendor Report
Signal: Successful Exploitation
Confidence: 80%
Source: cisa-kev
Details
| Cwes | CWE-22 |
|---|---|
| Feed | CISA Known Exploited Vulnerabilities Catalog |
| Product | MSHTML |
| Due Date | 2021-11-17 |
| Date Added | 2021-11-03 |
| Vendorproject | Microsoft |
| Vulnerabilityname | Microsoft MSHTML Remote Code Execution Vulnerability |
| Knownransomwarecampaignuse | Known |
References
Created: 2026-02-02 13:26 UTC
| Updated: 2026-02-06 07:53 UTC
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: a13133f8-8c70-4a10-a540-8a6cb57d7ecd
Exploited: Yes
Timestamps
First Seen: 2021-11-03
Asserted: 2021-11-03
Scope
Notes: KEVIntel entry: Microsoft MSHTML Remote Code Execution Vulnerability | Affected: Microsoft / Windows 10 Version 1809, Windows Server 2019, Windows Server 2019 (Server Core installation), Windows 10 Version 1909, Windows 10 Version 21H1, Windows Server 2022, Windows 10 Version 2004, Windows Server version 2004, Windows 10 Version 20H2, Windows Server version 20H2, Windows 10 Version 1507, Windows 10 Version 1607, Windows Server 2016, Windows Server 2016 (Server Core installation), Windows 7, Windows 7 Service Pack 1, Windows 8.1, Windows Server 2008 Service Pack 2, Windows Server 2008 Service Pack 2 (Server Core installation), Windows Server 2008 Service Pack 2, Windows Server 2008 R2 Service Pack 1, Windows Server 2008 R2 Service Pack 1 (Server Core installation), Windows Server 2012, Windows Server 2012 (Server Core installation), Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation) | CVSS: 8.8 (HIGH) | Used in malware: yes | Not yet in CISA KEV: False
Evidence
Type: Public Report
Signal: Confirmed Compromise
Confidence: 70%
Source: kevintel
Details
| Feed | KEVIntel (kevintel.com) |
|---|---|
| Title | Microsoft MSHTML Remote Code Execution Vulnerability |
| Vendor | Microsoft |
| Product | Windows 10 Version 1809, Windows Server 2019, Windows Server 2019 (Server Core installation), Windows 10 Version 1909, Windows 10 Version 21H1, Windows Server 2022, Windows 10 Version 2004, Windows Server version 2004, Windows 10 Version 20H2, Windows Server version 20H2, Windows 10 Version 1507, Windows 10 Version 1607, Windows Server 2016, Windows Server 2016 (Server Core installation), Windows 7, Windows 7 Service Pack 1, Windows 8.1, Windows Server 2008 Service Pack 2, Windows Server 2008 Service Pack 2 (Server Core installation), Windows Server 2008 Service Pack 2, Windows Server 2008 R2 Service Pack 1, Windows Server 2008 R2 Service Pack 1 (Server Core installation), Windows Server 2012, Windows Server 2012 (Server Core installation), Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation) |
| Added Date | 2021-11-03T00:00:00.000Z |
| Cvss Score | 8.8 |
| Epss Score | None |
| Cvss Severity | HIGH |
| Epss Percentile | None |
| Used In Malware | yes |
| Ahead Of Cisa Kev | None |
| Not Yet In Cisa Kev | False |
References
Created: 2026-06-23 11:13 UTC
| Updated: 2026-06-23 11:13 UTC
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-04T02:44:10.337Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40444"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "http://packetstormsecurity.com/files/164210/Microsoft-Windows-MSHTML-Overview.html"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "http://packetstormsecurity.com/files/165214/Microsoft-Office-Word-MSHTML-Remote-Code-Execution.html"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "http://packetstormsecurity.com/files/167317/Microsoft-Office-MSDT-Follina-Proof-Of-Concept.html"
}
],
"title": "CVE Program Container"
},
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2021-40444",
"options": [
{
"Exploitation": "active"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2021-09-08T00:00:00+00:00",
"version": "2.0.3"
},
"type": "ssvc"
}
},
{
"other": {
"content": {
"dateAdded": "2021-11-03",
"reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40444"
},
"type": "kev"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-22",
"description": "CWE-22 Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-03-11T03:55:26.291Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"government-resource"
],
"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40444"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1507",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.10240.19060",
"status": "affected",
"version": "10.0.10240.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1607",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.14393.4651",
"status": "affected",
"version": "10.0.14393.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1809",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.17763.2183",
"status": "affected",
"version": "10.0.17763.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"ARM64-based Systems"
],
"product": "Windows 10 Version 1809",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.17763.2183",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1909",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.18363.1801",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 2004",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19041.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems"
],
"product": "Windows 10 Version 20H2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19042.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 21H1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19043.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems"
],
"product": "Windows 7",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.1.7601.25712",
"status": "affected",
"version": "6.1.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows 7 Service Pack 1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.1.7601.25712",
"status": "affected",
"version": "6.1.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"product": "Windows 8.1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.3.9600.20120",
"status": "affected",
"version": "6.3.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2008 R2 Service Pack 1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.1.7601.25712",
"status": "affected",
"version": "6.1.7601.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2008 R2 Service Pack 1 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.1.7601.25712",
"status": "affected",
"version": "6.1.7601.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows Server 2008 Service Pack 2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.0.6003.21218",
"status": "affected",
"version": "6.0.6003.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows Server 2008 Service Pack 2 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.0.6003.21218",
"status": "affected",
"version": "6.0.6003.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2012",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.2.9200.23462",
"status": "affected",
"version": "6.2.9200.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2012 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.2.9200.23462",
"status": "affected",
"version": "6.2.9200.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2012 R2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.3.9600.20120",
"status": "affected",
"version": "6.3.9600.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2012 R2 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.3.9600.20120",
"status": "affected",
"version": "6.3.9600.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2016",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.14393.4651",
"status": "affected",
"version": "10.0.14393.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2016 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.14393.4651",
"status": "affected",
"version": "10.0.14393.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2019",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.17763.2183",
"status": "affected",
"version": "10.0.17763.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2019 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.17763.2183",
"status": "affected",
"version": "10.0.17763.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2022",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.20348.230",
"status": "affected",
"version": "10.0.20348.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server version 2004",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19041.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server version 20H2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19042.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*",
"versionEndExcluding": "10.0.17763.2183",
"versionStartIncluding": "10.0.17763.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:arm64:*",
"versionEndExcluding": "10.0.17763.2183",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.17763.2183",
"versionStartIncluding": "10.0.17763.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.17763.2183",
"versionStartIncluding": "10.0.17763.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1909:*:*:*:*:*:*:x86:*",
"versionEndExcluding": "10.0.18363.1801",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_21H1:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "10.0.19043.1237",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.20348.230",
"versionStartIncluding": "10.0.20348.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "10.0.19041.1237",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2004:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.19041.1237",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_20H2:*:*:*:*:*:*:x86:*",
"versionEndExcluding": "10.0.19042.1237",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_20H2:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.19042.1237",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1507:*:*:*:*:*:*:x86:*",
"versionEndExcluding": "10.0.10240.19060",
"versionStartIncluding": "10.0.10240.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*",
"versionEndExcluding": "10.0.14393.4651",
"versionStartIncluding": "10.0.14393.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.14393.4651",
"versionStartIncluding": "10.0.14393.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.14393.4651",
"versionStartIncluding": "10.0.14393.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_7:*:sp1:*:*:*:*:x86:*",
"versionEndExcluding": "6.1.7601.25712",
"versionStartIncluding": "6.1.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_7:*:sp1:*:*:*:*:x64:*",
"versionEndExcluding": "6.1.7601.25712",
"versionStartIncluding": "6.1.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_8.1:*:*:*:*:*:*:x86:*",
"versionEndExcluding": "6.3.9600.20120",
"versionStartIncluding": "6.3.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2008_sp2:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.0.6003.21218",
"versionStartIncluding": "6.0.6003.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2008_sp2:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.0.6003.21218",
"versionStartIncluding": "6.0.6003.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2008_R2:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.1.7601.25712",
"versionStartIncluding": "6.1.7601.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2008_R2:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.1.7601.25712",
"versionStartIncluding": "6.1.7601.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2012:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.2.9200.23462",
"versionStartIncluding": "6.2.9200.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2012:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.2.9200.23462",
"versionStartIncluding": "6.2.9200.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2012_R2:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.3.9600.20120",
"versionStartIncluding": "6.3.9600.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2012_R2:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.3.9600.20120",
"versionStartIncluding": "6.3.9600.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"datePublic": "2021-09-07T14:00:00.000Z",
"descriptions": [
{
"lang": "en-US",
"value": "Microsoft 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.\nAn 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.\nMicrosoft 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.\nUpon 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.\nPlease see the Mitigations and Workaround sections for important information about steps you can take to protect your system from this vulnerability.\nUPDATE 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."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L/E:P/RL:O/RC:C",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en-US",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "Remote Code Execution",
"lang": "en-US",
"type": "Impact"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-10T15:10:57.757Z",
"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"shortName": "microsoft"
},
"references": [
{
"name": "Microsoft MSHTML Remote Code Execution Vulnerability",
"tags": [
"vendor-advisory",
"patch"
],
"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-40444"
}
],
"title": "Microsoft MSHTML Remote Code Execution Vulnerability"
}
},
"cveMetadata": {
"assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"assignerShortName": "microsoft",
"cveId": "CVE-2021-40444",
"datePublished": "2021-09-15T11:24:26.000Z",
"dateReserved": "2021-09-02T00:00:00.000Z",
"dateUpdated": "2026-08-10T15:10:57.757Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"cisa_known_exploited": {
"cveID": "CVE-2021-40444",
"cwes": [
"CWE-22"
],
"dateAdded": "2021-11-03",
"dueDate": "2021-11-17",
"forensicTriage": "No",
"knownRansomwareCampaignUse": "Known",
"notes": "https://nvd.nist.gov/vuln/detail/CVE-2021-40444",
"product": "MSHTML",
"requiredAction": "Apply updates per vendor instructions.",
"shortDescription": "Microsoft MSHTML contains a unspecified vulnerability that allows for remote code execution.",
"vendorProject": "Microsoft",
"vulnerabilityName": "Microsoft MSHTML Remote Code Execution Vulnerability"
},
"epss": {
"cve": "CVE-2021-40444",
"date": "2026-09-20",
"epss": "0.9745",
"percentile": "0.99898"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1507",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.10240.19060",
"status": "affected",
"version": "10.0.10240.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1607",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.14393.4651",
"status": "affected",
"version": "10.0.14393.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1809",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.17763.2183",
"status": "affected",
"version": "10.0.17763.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"ARM64-based Systems"
],
"product": "Windows 10 Version 1809",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.17763.2183",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1909",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.18363.1801",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 2004",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19041.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems"
],
"product": "Windows 10 Version 20H2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19042.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 21H1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19043.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems"
],
"product": "Windows 7",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.1.7601.25712",
"status": "affected",
"version": "6.1.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows 7 Service Pack 1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.1.7601.25712",
"status": "affected",
"version": "6.1.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"product": "Windows 8.1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.3.9600.20120",
"status": "affected",
"version": "6.3.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2008 R2 Service Pack 1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.1.7601.25712",
"status": "affected",
"version": "6.1.7601.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2008 R2 Service Pack 1 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.1.7601.25712",
"status": "affected",
"version": "6.1.7601.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows Server 2008 Service Pack 2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.0.6003.21218",
"status": "affected",
"version": "6.0.6003.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows Server 2008 Service Pack 2 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.0.6003.21218",
"status": "affected",
"version": "6.0.6003.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2012",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.2.9200.23462",
"status": "affected",
"version": "6.2.9200.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2012 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.2.9200.23462",
"status": "affected",
"version": "6.2.9200.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2012 R2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.3.9600.20120",
"status": "affected",
"version": "6.3.9600.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2012 R2 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.3.9600.20120",
"status": "affected",
"version": "6.3.9600.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2016",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.14393.4651",
"status": "affected",
"version": "10.0.14393.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2016 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.14393.4651",
"status": "affected",
"version": "10.0.14393.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2019",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.17763.2183",
"status": "affected",
"version": "10.0.17763.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2019 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.17763.2183",
"status": "affected",
"version": "10.0.17763.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2022",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.20348.230",
"status": "affected",
"version": "10.0.20348.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server version 2004",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19041.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server version 20H2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19042.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
}
],
"source": "secure@microsoft.com"
}
],
"cisaActionDue": "2021-11-17",
"cisaExploitAdd": "2021-11-03",
"cisaRequiredAction": "Apply updates per vendor instructions.",
"cisaVulnerabilityName": "Microsoft MSHTML Remote Code Execution Vulnerability",
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1507:*:*:*:*:*:*:*:*",
"matchCriteriaId": "C1658517-428C-4FAF-8EEE-3FD68557AAD1",
"versionEndExcluding": "10.0.10240.19060",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:*:*",
"matchCriteriaId": "4BF6C51E-7240-457D-A36C-5494AEE41AB1",
"versionEndExcluding": "10.0.14393.4651",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:*:*",
"matchCriteriaId": "1673EF18-FB21-450C-B75D-89279B6779FA",
"versionEndExcluding": "10.0.17763.2183",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1909:*:*:*:*:*:*:*:*",
"matchCriteriaId": "F3F77B0B-2A62-4E21-B042-BB86ABA68BE3",
"versionEndExcluding": "10.0.18363.1801",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_2004:*:*:*:*:*:*:*:*",
"matchCriteriaId": "F4E719E7-7D50-49F6-ABD4-77B1F7ECC68C",
"versionEndExcluding": "10.0.19041.1237",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_20h2:*:*:*:*:*:*:*:*",
"matchCriteriaId": "71B3072F-0DB3-4C23-AD96-62BF71345E61",
"versionEndExcluding": "10.0.19042.1237",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_21h1:*:*:*:*:*:*:*:*",
"matchCriteriaId": "CB038EC1-8E36-48C1-8E2E-3B8B6585D25E",
"versionEndExcluding": "10.0.19043.1237",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:*:*",
"matchCriteriaId": "C2B1C231-DE19-4B8F-A4AA-5B3A65276E46",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:*:*",
"matchCriteriaId": "E93068DB-549B-45AB-8E5C-00EB5D8B5CF8",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_rt_8.1:-:*:*:*:*:*:*:*",
"matchCriteriaId": "C6CE5198-C498-4672-AF4C-77AB4BE06C5C",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2004:*:*:*:*:*:*:*:*",
"matchCriteriaId": "046119DC-43BF-4077-9721-12E2EFD7F492",
"versionEndExcluding": "10.0.19041.1237",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:*:*",
"matchCriteriaId": "5F422A8C-2C4E-42C8-B420-E0728037E15C",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*",
"matchCriteriaId": "AF07A81D-12E5-4B1D-BFF9-C8D08C32FF4F",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*",
"matchCriteriaId": "A7DF96F8-BA6A-4780-9CA3-F719B3F81074",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2012:-:r2:*:*:*:*:*:*",
"matchCriteriaId": "5F2558DF-2D1F-46BA-ABF1-08522D33268E",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*",
"matchCriteriaId": "EAF9D18C-B459-48F2-8451-20E7B04EAD36",
"versionEndExcluding": "10.0.14393.4651",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*",
"matchCriteriaId": "8867C828-131C-466E-9A35-80184659D540",
"versionEndExcluding": "10.0.17763.2183",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*",
"matchCriteriaId": "0663409D-4AE8-4BD9-85FE-9EAED15AE9DB",
"versionEndExcluding": "10.0.20348.230",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_20h2:*:*:*:*:*:*:*:*",
"matchCriteriaId": "292B87C7-3AC9-48FF-91D7-21D6D74C84A9",
"versionEndExcluding": "10.0.19042.1237",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Microsoft 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.\nAn 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.\nMicrosoft 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.\nUpon 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.\nPlease see the Mitigations and Workaround sections for important information about steps you can take to protect your system from this vulnerability.\nUPDATE 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."
},
{
"lang": "es",
"value": "Una Vulnerabilidad de Ejecuci\u00f3n de C\u00f3digo Remota de Microsoft MSHTML"
}
],
"id": "CVE-2021-40444",
"lastModified": "2026-08-10T20:19:30.393",
"metrics": {
"cvssMetricV2": [
{
"acInsufInfo": false,
"baseSeverity": "MEDIUM",
"cvssData": {
"accessComplexity": "MEDIUM",
"accessVector": "NETWORK",
"authentication": "NONE",
"availabilityImpact": "PARTIAL",
"baseScore": 6.8,
"confidentialityImpact": "PARTIAL",
"integrityImpact": "PARTIAL",
"vectorString": "AV:N/AC:M/Au:N/C:P/I:P/A:P",
"version": "2.0"
},
"exploitabilityScore": 8.6,
"impactScore": 6.4,
"obtainAllPrivilege": false,
"obtainOtherPrivilege": false,
"obtainUserPrivilege": false,
"source": "nvd@nist.gov",
"type": "Primary",
"userInteractionRequired": true
}
],
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "LOW",
"baseScore": 8.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "LOW",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L",
"version": "3.1"
},
"exploitabilityScore": 2.8,
"impactScore": 5.3,
"source": "secure@microsoft.com",
"type": "Secondary"
},
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "nvd@nist.gov",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2021-40444",
"options": [
{
"exploitation": "active"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2021-09-08T00:00:00+00:00",
"version": "2.0.3"
}
}
]
},
"published": "2021-09-15T12:15:16.467",
"references": [
{
"source": "secure@microsoft.com",
"tags": [
"Patch",
"Vendor Advisory"
],
"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-40444"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
"Third Party Advisory",
"VDB Entry"
],
"url": "http://packetstormsecurity.com/files/164210/Microsoft-Windows-MSHTML-Overview.html"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
"Exploit",
"Third Party Advisory",
"VDB Entry"
],
"url": "http://packetstormsecurity.com/files/165214/Microsoft-Office-Word-MSHTML-Remote-Code-Execution.html"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
"Exploit",
"Third Party Advisory",
"VDB Entry"
],
"url": "http://packetstormsecurity.com/files/167317/Microsoft-Office-MSDT-Follina-Proof-Of-Concept.html"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
"Mitigation",
"Patch",
"Vendor Advisory"
],
"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40444"
},
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"tags": [
"US Government Resource"
],
"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40444"
}
],
"sourceIdentifier": "secure@microsoft.com",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-22"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
},
{
"description": [
{
"lang": "en",
"value": "CWE-22"
}
],
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
]
}
},
"redhat_vex": {
"current_release_date": "2026-03-27T13:34:38+00:00",
"cve": "CVE-2021-40444",
"id": "CVE-2021-40444",
"initial_release_date": "2021-09-07T07:00:00+00:00",
"product_status:known_not_affected": "1",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "Microsoft MSHTML Remote Code Execution Vulnerability",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-40444.json",
"version": "3"
},
"vulnrichment": {
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-04T02:44:10.337Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40444"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "http://packetstormsecurity.com/files/164210/Microsoft-Windows-MSHTML-Overview.html"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "http://packetstormsecurity.com/files/165214/Microsoft-Office-Word-MSHTML-Remote-Code-Execution.html"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "http://packetstormsecurity.com/files/167317/Microsoft-Office-MSDT-Follina-Proof-Of-Concept.html"
}
],
"title": "CVE Program Container"
},
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2021-40444",
"options": [
{
"Exploitation": "active"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2025-12-16T17:57:49.233131Z",
"version": "2.0.3"
},
"type": "ssvc"
}
},
{
"other": {
"content": {
"dateAdded": "2021-11-03",
"reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40444"
},
"type": "kev"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-22",
"description": "CWE-22 Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2025-02-04T14:44:49.785Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"government-resource"
],
"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40444"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1507",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.10240.19060",
"status": "affected",
"version": "10.0.10240.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1607",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.14393.4651",
"status": "affected",
"version": "10.0.14393.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1809",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.17763.2183",
"status": "affected",
"version": "10.0.17763.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"ARM64-based Systems"
],
"product": "Windows 10 Version 1809",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.17763.2183",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1909",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.18363.1801",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 2004",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19041.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems"
],
"product": "Windows 10 Version 20H2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19042.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 21H1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19043.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems"
],
"product": "Windows 7",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.1.7601.25712",
"status": "affected",
"version": "6.1.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows 7 Service Pack 1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.1.7601.25712",
"status": "affected",
"version": "6.1.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"product": "Windows 8.1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.3.9600.20120",
"status": "affected",
"version": "6.3.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2008 R2 Service Pack 1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.1.7601.25712",
"status": "affected",
"version": "6.1.7601.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2008 R2 Service Pack 1 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.1.7601.25712",
"status": "affected",
"version": "6.1.7601.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows Server 2008 Service Pack 2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.0.6003.21218",
"status": "affected",
"version": "6.0.6003.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows Server 2008 Service Pack 2 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.0.6003.21218",
"status": "affected",
"version": "6.0.6003.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2012",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.2.9200.23462",
"status": "affected",
"version": "6.2.9200.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2012 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.2.9200.23462",
"status": "affected",
"version": "6.2.9200.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2012 R2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.3.9600.20120",
"status": "affected",
"version": "6.3.9600.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2012 R2 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "6.3.9600.20120",
"status": "affected",
"version": "6.3.9600.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2016",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.14393.4651",
"status": "affected",
"version": "10.0.14393.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2016 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.14393.4651",
"status": "affected",
"version": "10.0.14393.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2019",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.17763.2183",
"status": "affected",
"version": "10.0.17763.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2019 (Server Core installation)",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.17763.2183",
"status": "affected",
"version": "10.0.17763.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2022",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.20348.230",
"status": "affected",
"version": "10.0.20348.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server version 2004",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19041.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Windows Server version 20H2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.19042.1237",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*",
"versionEndExcluding": "10.0.17763.2183",
"versionStartIncluding": "10.0.17763.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:arm64:*",
"versionEndExcluding": "10.0.17763.2183",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.17763.2183",
"versionStartIncluding": "10.0.17763.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.17763.2183",
"versionStartIncluding": "10.0.17763.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1909:*:*:*:*:*:*:x86:*",
"versionEndExcluding": "10.0.18363.1801",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_21H1:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "10.0.19043.1237",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.20348.230",
"versionStartIncluding": "10.0.20348.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "10.0.19041.1237",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2004:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.19041.1237",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_20H2:*:*:*:*:*:*:x86:*",
"versionEndExcluding": "10.0.19042.1237",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_20H2:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.19042.1237",
"versionStartIncluding": "10.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1507:*:*:*:*:*:*:x86:*",
"versionEndExcluding": "10.0.10240.19060",
"versionStartIncluding": "10.0.10240.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*",
"versionEndExcluding": "10.0.14393.4651",
"versionStartIncluding": "10.0.14393.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.14393.4651",
"versionStartIncluding": "10.0.14393.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*",
"versionEndExcluding": "10.0.14393.4651",
"versionStartIncluding": "10.0.14393.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_7:*:sp1:*:*:*:*:x86:*",
"versionEndExcluding": "6.1.7601.25712",
"versionStartIncluding": "6.1.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_7:*:sp1:*:*:*:*:x64:*",
"versionEndExcluding": "6.1.7601.25712",
"versionStartIncluding": "6.1.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_8.1:*:*:*:*:*:*:x86:*",
"versionEndExcluding": "6.3.9600.20120",
"versionStartIncluding": "6.3.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2008_sp2:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.0.6003.21218",
"versionStartIncluding": "6.0.6003.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2008_sp2:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.0.6003.21218",
"versionStartIncluding": "6.0.6003.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2008_R2:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.1.7601.25712",
"versionStartIncluding": "6.1.7601.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2008_R2:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.1.7601.25712",
"versionStartIncluding": "6.1.7601.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2012:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.2.9200.23462",
"versionStartIncluding": "6.2.9200.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2012:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.2.9200.23462",
"versionStartIncluding": "6.2.9200.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2012_R2:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.3.9600.20120",
"versionStartIncluding": "6.3.9600.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:microsoft:windows_server_2012_R2:*:*:*:*:*:*:x64:*",
"versionEndExcluding": "6.3.9600.20120",
"versionStartIncluding": "6.3.9600.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"datePublic": "2021-09-07T14:00:00.000Z",
"descriptions": [
{
"lang": "en-US",
"value": "Microsoft 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.\nAn 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.\nMicrosoft 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.\nUpon 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.\nPlease see the Mitigations and Workaround sections for important information about steps you can take to protect your system from this vulnerability.\nUPDATE 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."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L/E:P/RL:O/RC:C",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en-US",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "Remote Code Execution",
"lang": "en-US",
"type": "Impact"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-10T15:10:57.757Z",
"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"shortName": "microsoft"
},
"references": [
{
"name": "Microsoft MSHTML Remote Code Execution Vulnerability",
"tags": [
"vendor-advisory",
"patch"
],
"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-40444"
}
],
"title": "Microsoft MSHTML Remote Code Execution Vulnerability"
}
},
"cveMetadata": {
"assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"assignerShortName": "microsoft",
"cveId": "CVE-2021-40444",
"datePublished": "2021-09-15T11:24:26.000Z",
"dateReserved": "2021-09-02T00:00:00.000Z",
"dateUpdated": "2026-08-10T15:10:57.757Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
Loading…