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 / Microsoft System Center Endpoint Protection
Default status: Not specified
- affected: N/A
Microsoft / Microsoft System Center 2012 R2 Endpoint Protection
Default status: Not specified
- affected: N/A
Microsoft / Microsoft Security Essentials
Default status: Not specified
- affected: N/A
Microsoft / Microsoft System Center 2012 Endpoint Protection
Default status: Not specified
- affected: N/A
Microsoft / Windows Defender
Default status: Not specified
- affected: N/A
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": 0.39653,
"percentile": 0.98639
}10 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-10",
"epss": 0.39653,
"percentile": 0.98631
}09 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-09",
"epss": 0.39653,
"percentile": 0.98629
}08 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-08",
"epss": 0.39653,
"percentile": 0.98628
}07 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-07",
"epss": 0.39653,
"percentile": 0.98627
}06 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-06",
"epss": 0.39653,
"percentile": 0.98625
}06 Nov 2026, 00:20 Jerusalem · CVE Program record changed
Stored CNA snapshot at this observation.
{
"containers": {
"adp": [
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"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1647"
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{
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"title": "CISA ADP Vulnrichment"
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],
"cna": {
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{
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{
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{
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"platforms": [
"Windows 10 Version 1803 for 32-bit Systems",
"Windows 10 Version 1803 for x64-based Systems",
"Windows 10 Version 1803 for ARM64-based Systems",
"Windows 10 Version 1809 for 32-bit Systems",
"Windows 10 Version 1809 for x64-based Systems",
"Windows 10 Version 1809 for ARM64-based Systems",
"Windows Server 2019",
"Windows Server 2019 (Server Core installation)",
"Windows 10 Version 1909 for 32-bit Systems",
"Windows 10 Version 1909 for x64-based Systems",
"Windows 10 Version 1909 for ARM64-based Systems",
"Windows Server, version 1909 (Server Core installation)",
"Windows 10 Version 2004 for 32-bit Systems",
"Windows 10 Version 2004 for ARM64-based Systems",
"Windows 10 Version 2004 for x64-based Systems",
"Windows Server, version 2004 (Server Core installation)",
"Windows 10 Version 20H2 for 32-bit Systems",
"Windows 10 Version 20H2 for ARM64-based Systems",
"Windows Server, version 20H2 (Server Core Installation)",
"Windows 10 for 32-bit Systems",
"Windows 10 for x64-based Systems",
"Windows 10 Version 1607 for 32-bit Systems",
"Windows 10 Version 1607 for x64-based Systems",
"Windows Server 2016",
"Windows Server 2016 (Server Core installation)",
"Windows 7 for 32-bit Systems Service Pack 1",
"Windows 7 for x64-based Systems Service Pack 1",
"Windows 8.1 for 32-bit systems",
"Windows 8.1 for x64-based systems",
"Windows RT 8.1",
"Windows Server 2008 for 32-bit Systems Service Pack 2",
"Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)",
"Windows Server 2008 R2 for x64-based Systems Service Pack 1",
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"Windows Server 2012",
"Windows Server 2012 (Server Core installation)",
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"version": "3.1"
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],
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],
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},
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{
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"tags": [
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],
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}
],
"title": "Microsoft Defender Remote Code Execution Vulnerability"
}
},
"cveMetadata": {
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"datePublished": "2021-01-12T19:42:01.000Z",
"dateReserved": "2020-12-02T00:00:00.000Z",
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"state": "PUBLISHED"
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}05 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-05",
"epss": 0.39653,
"percentile": 0.98624
}04 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-04",
"epss": 0.39653,
"percentile": 0.98622
}03 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-03",
"epss": 0.39653,
"percentile": 0.98619
}03 Nov 2026, 02:22 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-02",
"epss": 0.39653,
"percentile": 0.98617
}03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed
Stored KEV snapshot at this observation.
{
"cveID": "CVE-2021-1647",
"cwes": [
"CWE-122",
"CWE-1285"
],
"dateAdded": "2021-11-03",
"dueDate": "2021-11-17",
"forensicTriage": "No",
"knownRansomwareCampaignUse": "Unknown",
"notes": "https://nvd.nist.gov/vuln/detail/CVE-2021-1647",
"product": "Defender",
"requiredAction": "Apply updates per vendor instructions.",
"shortDescription": "Microsoft Defender contains an unspecified vulnerability that allows for remote code execution.",
"vendorProject": "Microsoft",
"vulnerabilityName": "Microsoft Defender Remote Code Execution Vulnerability"
}