Security readout for executives and security teams
Plain-English summary
CVE-2021-42278 is a Microsoft Active Directory Domain Services privilege escalation issue. For executives, the concern is domain identity compromise: a low-privileged attacker could potentially gain higher privileges if affected Windows Server AD DS systems are unpatched.
Executive priority
Treat as a high-priority identity infrastructure risk. Because CISA marks it as known exploited, remediation should be tracked as an urgent operational item, especially for domain controllers.
Technical view
The source bundle lists a CVSS 3.1 score of 7.5 with network attack vector, low privileges required, high complexity, no user interaction, and high confidentiality, integrity, and availability impact. Microsoft identifies affected Windows Server versions from 2008 through 2022.
Likely exposure
Exposure is most likely in organizations running affected Windows Server systems that host Active Directory Domain Services and have not applied Microsoft’s CVE-2021-42278 security updates.
Exploitation context
CISA lists CVE-2021-42278 in the Known Exploited Vulnerabilities catalog, so active exploitation is source-supported. The provided sources do not include exploit mechanics, attacker tooling, or campaign details.
Researcher notes
The bundle provides affected products, CVSS vector, MSRC advisory, and KEV status, but no CWE or root-cause details. Avoid assuming exploit chains or specific primitives beyond AD DS elevation of privilege unless confirmed by vendor or trusted analysis.
Mitigation direction
- Apply Microsoft security updates referenced by the MSRC advisory.
- Prioritize domain controllers and AD DS servers first.
- Review CISA KEV deadlines and internal remediation SLAs.
- Confirm legacy Windows Server systems receive applicable supported updates.
- Check Microsoft guidance for any version-specific prerequisites or notes.
Validation and detection
- Inventory Windows Server AD DS hosts by version and patch level.
- Verify CVE-2021-42278 update installation against Microsoft guidance.
- Check vulnerability scanner findings for remaining affected CPEs.
- Review domain controller patch compliance reports.
- Document exceptions for unsupported or isolated systems.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
Privilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-42278 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C1.65.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42278CVE reference · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42278CVE reference · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.