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CVE-2021-42278

90
FAUCET Score

CVE-2021-42278 is an Active Directory Domain Services Elevation of Privilege vulnerability affecting multiple versions of Microsoft Windows Server. This high-severity flaw (CVSS 7.5) allows a low-privileged attacker to achieve full domain takeover with high impact on confidentiality, integrity, and availability, despite requiring high attack complexity. The vulnerability is actively exploited in the wild, including by ransomware campaigns, and has garnered significant community discussion and media attention, although public exploit code is not readily available.

Impacted Technologies

VendorProductVersion(s)CPE
< 10.0.19041.1348CPE matchmatch criteria
cpe:2.3:o:microsoft:windows_server_2004:*:*:*:*:*:*:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:*:*
r2CPE matchmatch criteria
cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
r2CPE matchmatch criteria
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.6
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
70.21%
Probability of exploitation in next 30 days
EPSS Percentile
99.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
Added to KEV · Apr 11, 2022
This CVE's current EPSS score of 0.7021 is in the 99th percentile among its peer group of 1,162 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (19)

microsoftpatch availablevia nvd_reference
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2019Fixed in: 10.0.17763.2300
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2019 (Server Core installation)Fixed in: 10.0.17763.2300
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2022Fixed in: 10.0.20348.350
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2022 (Server Core installation)Fixed in: 10.0.20348.350
View patch
microsoftpatch availablevia msrc
Product: Windows Server, version 2004 (Server Core installation)Fixed in: 10.0.19041.1348
View patch
microsoftpatch availablevia msrc
Product: Windows Server, version 20H2 (Server Core Installation)Fixed in: 10.0.19042.1348
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2016Fixed in: 10.0.14393.4770
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2016 (Server Core installation)Fixed in: 10.0.14393.4770
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2008 for 32-bit Systems Service Pack 2Fixed in: 6.0.6003.21282
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)Fixed in: 6.0.6003.21282
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2008 for x64-based Systems Service Pack 2Fixed in: 6.0.6003.21282
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)Fixed in: 6.0.6003.21282
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2008 R2 for x64-based Systems Service Pack 1Fixed in: 6.1.7601.25769
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)Fixed in: 6.1.7601.25769
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2012Fixed in: 6.2.9200.23517
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2012 (Server Core installation)Fixed in: 6.2.9200.23517
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2012 R2Fixed in: 6.3.9600.20174
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2012 R2 (Server Core installation)Fixed in: 6.3.9600.20174
View patch

Vendor Advisories (1)

microsoft2021-Nov/CVE-2021-42278Important

Active Directory Domain Services Elevation of Privilege Vulnerability

Nov 9, 2021

References

cisa.gov / known-exploited-vulnerabilities-catalog
US Government Resource
portal.msrc.microsoft.com / en-US/security-guidance/advisory/CVE-2021-42278
PatchVendor Advisory