CISA KEV · Known exploitedHigh

CVE-2021-42278

Microsoft Active Directory

CVE-2021-42278 affects Microsoft Active Directory. Review the CVSS score, exploitation signals, affected versions, remediation status, and linked source material before making a change.

CVSS: 7.5
EPSS: 70.2%
CISA KEV: Listed
Published: 2021.11.10

PRIORITY ASSESSMENT

Immediate review

CISA has listed this vulnerability in the Known Exploited Vulnerabilities catalog.

Known exploitationConfirmed by CISA KEV

Exploit probability70.2%

Technical severityCVSS 7.5

Vulnerability overview

CVE-2021-42278 affects Microsoft Active Directory. Review the CVSS score, exploitation signals, affected versions, remediation status, and linked source material before making a change.

Affected product and versions

Product: Microsoft Active Directory
Affected versions: 10.0.0, 6.0.0, 6.1.0, 6.2.0, 6.3.0, < 10.0.19041.1348, r2, < 10.0.14393.4770, < 10.0.17763.2300, < 10.0.20348.350, < 10.0.19042.1348
Fixed versions: 10.0.19041.1348, 10.0.14393.4770, 10.0.17763.2300, 10.0.20348.350, 10.0.19042.1348

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

CISA required action

Apply updates per vendor instructions.

Due date: 2022.05.02

1
Identify
Confirm that Microsoft Active Directory and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE: CWE-20
KEV added: 2022.04.11
Ransomware use: 확인됨