Exploitation evidence
Known exploited · CISA KEV listed
Added 2021-11-03. Ransomware campaign use: Unknown.
CISA required action: Apply updates per vendor instructions.
CISA due date: 2021-11-17. This is the catalog’s deadline, not an assessment of your organization’s exposure.
KEV checked 13 Nov 2026, 00:20 Jerusalem · Original catalog ↗Reported products and versions
Microsoft / Windows 10 Version 1809
Default status: Not specified
- affected: 10.0.0 to < 10.0.17763.1999 (custom)
Microsoft / Windows Server 2019
Default status: Not specified
- affected: 10.0.0 to < 10.0.17763.1999 (custom)
Microsoft / Windows 10 Version 1909
Default status: Not specified
- affected: 10.0.0 to < 10.0.18363.1621 (custom)
Microsoft / Windows 10 Version 21H1
Default status: Not specified
- affected: 10.0.0 to < 10.0.19043.1052 (custom)
Microsoft / Windows 10 Version 2004
Default status: Not specified
- affected: 10.0.0 to < 10.0.19041.1052 (custom)
Microsoft / Windows 10 Version 20H2
Default status: Not specified
- affected: 10.0.0 to < 10.0.19042.1052 (custom)
Microsoft / Windows 10 Version 1507
Default status: Not specified
- affected: 10.0.0 to < 10.0.10240.18967 (custom)
Microsoft / Windows 10 Version 1607
Default status: Not specified
- affected: 10.0.0 to < 10.0.14393.4467 (custom)
Microsoft / Windows Server 2016
Default status: Not specified
- affected: 10.0.0 to < 10.0.14393.4467 (custom)
Microsoft / Windows 7
Default status: Not specified
- affected: 6.1.0 to < 6.1.7601.25632 (custom)
- affected: 6.1.0 to < publication (custom)
Microsoft / Windows 7 Service Pack 1
Default status: Not specified
- affected: 6.1.0 to < 6.1.7601.25632 (custom)
- affected: 6.1.0 to < publication (custom)
Microsoft / Windows 8.1
Default status: Not specified
- affected: 6.3.0 to < 6.3.9600.20045 (custom)
- affected: 6.3.0 to < 1.0.0.0 (custom)
Microsoft / Windows Server 2008 Service Pack 2
Default status: Not specified
- affected: 6.0.0 to < 6.0.6003.21137 (custom)
- affected: 6.0.0 to < publication (custom)
Microsoft / Windows Server 2008 Service Pack 2
Default status: Not specified
- affected: 6.0.0 to < 6.0.6003.21137 (custom)
- affected: 6.0.0 to < publication (custom)
Microsoft / Windows Server 2008 R2 Service Pack 1
Default status: Not specified
- affected: 6.1.0 to < 6.1.7601.25632 (custom)
- affected: 6.1.0 to < publication (custom)
Microsoft / Windows Server 2012
Default status: Not specified
- affected: 6.2.0 to < 6.2.9200.23372 (custom)
- affected: 6.2.0 to < 1.0.0.0 (custom)
Microsoft / Windows Server 2012 R2
Default status: Not specified
- affected: 6.3.0 to < 6.3.9600.20045 (custom)
- affected: 6.3.0 to < 1.0.0.0 (custom)
Fixes and workarounds
No explicit solution text in the downloaded CVE record. Consult the vendor advisory; unaffected version ranges are shown above as reported, not inferred as a patch recommendation.
Sources and related reporting
Observed change timeline
History begins when Egret first downloads each source. It is not the complete upstream CVE history.
12 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-12",
"epss": 0.59407,
"percentile": 0.99135
}10 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-10",
"epss": 0.59407,
"percentile": 0.9913
}09 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-09",
"epss": 0.59407,
"percentile": 0.99128
}08 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-08",
"epss": 0.59407,
"percentile": 0.99128
}07 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-07",
"epss": 0.59407,
"percentile": 0.99127
}06 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-06",
"epss": 0.59407,
"percentile": 0.99126
}06 Nov 2026, 06:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-05",
"epss": 0.59407,
"percentile": 0.99125
}05 Nov 2026, 12:20 Jerusalem · CVE Program record changed
Stored CNA snapshot at this observation.
{
"containers": {
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"title": "CVE Program Container"
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{
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"version": "2.0.3"
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"product": "Windows 10 Version 21H1",
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"product": "Windows 10 Version 2004",
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{
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"ARM64-based Systems"
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"product": "Windows 10 Version 20H2",
"vendor": "Microsoft",
"versions": [
{
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},
{
"cpes": [
"cpe:2.3:o:microsoft:windows_10_1507:10.0.10240.18967:*:*:*:*:*:x86:*",
"cpe:2.3:o:microsoft:windows_10_1507:10.0.10240.18967:*:*:*:*:*:x64:*"
],
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1507",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "10.0.10240.18967",
"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
"cpes": [
"cpe:2.3:o:microsoft:windows_10_1607:10.0.14393.4467:*:*:*:*:*:x86:*",
"cpe:2.3:o:microsoft:windows_10_1607:10.0.14393.4467:*:*:*:*:*:x64:*"
],
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"product": "Windows 10 Version 1607",
"vendor": "Microsoft",
"versions": [
{
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"status": "affected",
"version": "10.0.0",
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{
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"platforms": [
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"product": "Windows Server 2016",
"vendor": "Microsoft",
"versions": [
{
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"status": "affected",
"version": "10.0.0",
"versionType": "custom"
}
]
},
{
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"cpe:2.3:o:microsoft:windows_7:6.1.7601.25632:sp1:*:*:*:*:x86:*",
"cpe:2.3:o:microsoft:windows_7:*:sp1:*:*:*:*:x86:*"
],
"platforms": [
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],
"product": "Windows 7",
"vendor": "Microsoft",
"versions": [
{
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"status": "affected",
"version": "6.1.0",
"versionType": "custom"
},
{
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"status": "affected",
"version": "6.1.0",
"versionType": "custom"
}
]
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{
"cpes": [
"cpe:2.3:o:microsoft:windows_7:6.1.7601.25632:sp1:*:*:*:*:x64:*",
"cpe:2.3:o:microsoft:windows_7:*:sp1:*:*:*:*:x64:*"
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"platforms": [
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],
"product": "Windows 7 Service Pack 1",
"vendor": "Microsoft",
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{
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{
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},
{
"cpes": [
"cpe:2.3:o:microsoft:windows_8.1:6.3.9600.20045:*:*:*:*:*:x86:*",
"cpe:2.3:o:microsoft:windows_8.1:1.0.0.0:*:*:*:*:*:x86:*",
"cpe:2.3:o:microsoft:windows_8.1:6.3.9600.20045:*:*:*:*:*:x64:*",
"cpe:2.3:o:microsoft:windows_8.1:1.0.0.0:*:*:*:*:*:x64:*",
"cpe:2.3:o:microsoft:windows_rt_8.1:6.3.9600.20045:*:*:*:*:*:*:*"
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"platforms": [
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"x64-based Systems",
"ARM64-based Systems"
],
"product": "Windows 8.1",
"vendor": "Microsoft",
"versions": [
{
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"status": "affected",
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{
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{
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{
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"vendor": "Microsoft",
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{
"cpes": [
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],
"product": "Windows Server 2012",
"vendor": "Microsoft",
"versions": [
{
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"versionType": "custom"
},
{
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"status": "affected",
"version": "6.2.0",
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]
},
{
"cpes": [
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"cpe:2.3:o:microsoft:windows_server_2012_R2:1.0.0.0:*:*:*:*:*:x64:*"
],
"platforms": [
"x64-based Systems"
],
"product": "Windows Server 2012 R2",
"vendor": "Microsoft",
"versions": [
{
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"status": "affected",
"version": "6.3.0",
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},
{
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"status": "affected",
"version": "6.3.0",
"versionType": "custom"
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]
}
],
"datePublic": "2021-06-08T07:00:00.000Z",
"descriptions": [
{
"lang": "en-US",
"value": "Windows MSHTML Platform Remote Code Execution Vulnerability"
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.5,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/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": "2024-05-29T14:55:49.884Z",
"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"shortName": "microsoft"
},
"references": [
{
"tags": [
"x_refsource_MISC"
],
"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33742"
}
],
"title": "Windows MSHTML Platform Remote Code Execution Vulnerability"
}
},
"cveMetadata": {
"assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"assignerShortName": "microsoft",
"cveId": "CVE-2021-33742",
"datePublished": "2021-06-08T22:46:44.000Z",
"dateReserved": "2021-05-28T00:00:00.000Z",
"dateUpdated": "2025-10-21T23:25:42.892Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1"
}04 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-04",
"epss": 0.59407,
"percentile": 0.99124
}03 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-03",
"epss": 0.59407,
"percentile": 0.99122
}03 Nov 2026, 02:22 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-02",
"epss": 0.59407,
"percentile": 0.99121
}03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed
Stored KEV snapshot at this observation.
{
"cveID": "CVE-2021-33742",
"cwes": [
"CWE-787",
"CWE-823"
],
"dateAdded": "2021-11-03",
"dueDate": "2021-11-17",
"forensicTriage": "No",
"knownRansomwareCampaignUse": "Unknown",
"notes": "https://nvd.nist.gov/vuln/detail/CVE-2021-33742",
"product": "Windows",
"requiredAction": "Apply updates per vendor instructions.",
"shortDescription": "Microsoft Windows MSHTML Platform contains an unspecified vulnerability that allows for remote code execution.",
"vendorProject": "Microsoft",
"vulnerabilityName": "Microsoft Windows MSHTML Platform Remote Code Execution Vulnerability"
}