CVE-2021-42278VulnerabilityPublished 04/11/2022Updated 10/24/2026

CVE-2021-42278: Microsoft Active Directory Domain Services Privilege Escalation Vulnerability

Affects Microsoft Active DirectorySource CISA KEV

Severity

High

No CVSS score published yet

Exploitation: Actively exploited – in CISA KEV since 04/11/2022
KEV deadline: 05/02/2022
Ransomware: Used in ransomware campaigns
EPSS: 73.3% chance of exploitation in 30 days – higher than 99% of CVEs

What to do

CISA required action

Apply updates per vendor instructions.

nvd.nist.gov/vuln/detail/CVE-2021-42278 (opens in a new tab)

Description

CVE-2021-42278 is a high-severity privilege escalation vulnerability in Microsoft Active Directory Domain Services. The vulnerability allows an attacker to escalate privileges within an Active Directory environment. It has been exploited in the wild and is known to have been used in ransomware campaigns. No specific affected versions or patch information is provided in the available data.

Summary

Microsoft Active Directory Domain Services contains an unspecified vulnerability identified as CVE-2021-42278 that enables privilege escalation. The vulnerability has been observed in active exploitation scenarios, including ransomware campaigns. Details on the exact nature of the flaw or affected versions are not provided in the input data. No patch or remediation information is available from the vendor in the provided context.

Impact

Successful exploitation of this vulnerability allows an attacker to escalate privileges within Active Directory, potentially leading to unauthorized administrative access. This can facilitate further compromise of network resources and enable ransomware deployment, as evidenced by known ransomware campaign use.

Mitigation

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until official fixes or mitigations are confirmed, organizations should monitor for related threat activity and apply any recommended security controls from Microsoft advisories.

Weaknesses

CWE-20Improper Input Validation (opens in a new tab)

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 11:26:05 UTC

Weaknesses

References

Related threats