Exploitation evidence
Known exploited · CISA KEV listed
Added 2022-04-11. Ransomware campaign use: Known.
CISA required action: Apply updates per vendor instructions.
CISA due date: 2022-05-02. 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 Server 2008 R2 Service Pack 1
Default status: Not specified
- affected: 6.1.7601.0 to < 6.1.7601.25769 (custom)
Microsoft / Windows Server 2008 R2 Service Pack 1 (Server Core installation)
Default status: Not specified
- affected: 6.1.7601.0 to < 6.1.7601.25769 (custom)
Microsoft / Windows Server 2008 Service Pack 2
Default status: Not specified
- affected: 6.0.6003.0 to < 6.0.6003.21282 (custom)
Microsoft / Windows Server 2008 Service Pack 2 (Server Core installation)
Default status: Not specified
- affected: 6.0.6003.0 to < 6.0.6003.21282 (custom)
Microsoft / Windows Server 2012
Default status: Not specified
- affected: 6.2.9200.0 to < 6.2.9200.23517 (custom)
Microsoft / Windows Server 2012 (Server Core installation)
Default status: Not specified
- affected: 6.2.9200.0 to < 6.2.9200.23517 (custom)
Microsoft / Windows Server 2012 R2
Default status: Not specified
- affected: 6.3.9600.0 to < 6.3.9600.20174 (custom)
Microsoft / Windows Server 2012 R2 (Server Core installation)
Default status: Not specified
- affected: 6.3.9600.0 to < 6.3.9600.20174 (custom)
Microsoft / Windows Server 2016
Default status: Not specified
- affected: 10.0.14393.0 to < 10.0.14393.4770 (custom)
Microsoft / Windows Server 2016 (Server Core installation)
Default status: Not specified
- affected: 10.0.14393.0 to < 10.0.14393.4770 (custom)
Microsoft / Windows Server 2019
Default status: Not specified
- affected: 10.0.17763.0 to < 10.0.17763.2300 (custom)
Microsoft / Windows Server 2019 (Server Core installation)
Default status: Not specified
- affected: 10.0.17763.0 to < 10.0.17763.2300 (custom)
Microsoft / Windows Server 2022
Default status: Not specified
- affected: 10.0.20348.0 to < 10.0.20348.350 (custom)
Microsoft / Windows Server version 2004
Default status: Not specified
- affected: 10.0.0 to < 10.0.19041.1348 (custom)
Microsoft / Windows Server version 20H2
Default status: Not specified
- affected: 10.0.0 to < 10.0.19042.1348 (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
CVE Program record ↗ · Download tracked evidence as JSON
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-42278
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42278
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42278
Monitored source mentions
Shared CVE identifiers link source mentions; they do not establish that the reports describe the same incident.
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": 0.73297,
"percentile": 0.99468
}10 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-10",
"epss": 0.73297,
"percentile": 0.99465
}09 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-09",
"epss": 0.73297,
"percentile": 0.99464
}08 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-08",
"epss": 0.73297,
"percentile": 0.99464
}07 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-07",
"epss": 0.73297,
"percentile": 0.99464
}06 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-06",
"epss": 0.73297,
"percentile": 0.99463
}06 Nov 2026, 06:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-05",
"epss": 0.73297,
"percentile": 0.99463
}05 Nov 2026, 06:20 Jerusalem · CVE Program record changed
Stored CNA snapshot at this observation.
{
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"state": "PUBLISHED"
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}04 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-04",
"epss": 0.73297,
"percentile": 0.99462
}03 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-03",
"epss": 0.73297,
"percentile": 0.99461
}03 Nov 2026, 02:22 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-02",
"epss": 0.73297,
"percentile": 0.9946
}03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed
Stored KEV snapshot at this observation.
{
"cveID": "CVE-2021-42278",
"cwes": [
"CWE-20"
],
"dateAdded": "2022-04-11",
"dueDate": "2022-05-02",
"forensicTriage": "No",
"knownRansomwareCampaignUse": "Known",
"notes": "https://nvd.nist.gov/vuln/detail/CVE-2021-42278",
"product": "Active Directory",
"requiredAction": "Apply updates per vendor instructions.",
"shortDescription": "Microsoft Active Directory Domain Services contains an unspecified vulnerability that allows for privilege escalation.",
"vendorProject": "Microsoft",
"vulnerabilityName": "Microsoft Active Directory Domain Services Privilege Escalation Vulnerability"
}