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Full vulnerability report · 2021
CVE-2021-42278High confidence

Microsoft Active Directory Domain Services Privilege Escalation Vulnerability

Microsoft · Active Directory

7.5HighCVSS 3.1
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2022-05-02 as the remediation due date.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:Critical, raised one band.upgradedsince 11 Apr 2022

Evidence used

  • CISA confirms exploitation in the wild.
  • EPSS is 73.30% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Microsoft Active Directory and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2021-29254

CISA KEV mirrored by ENISA

Active Directory Domain Services Elevation of Privilege Vulnerability

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 11 Apr 2022. Evidence sources: cisa_kev.
ENISA score
7.5 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2022-05-02 as the remediation due date.

Patch available
01

What, why and how

Microsoft Active Directory Domain Services contains an unspecified vulnerability that allows for privilege escalation.

What

Microsoft Active Directory Domain Services contains an unspecified vulnerability that allows for privilege escalation.

Why

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may gain additional privileges.

What

Microsoft Active Directory Domain Services contains an unspecified vulnerability that allows for privilege escalation.

Why

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may gain additional privileges.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2022-04-11. Known ransomware campaign use is recorded.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Input Validation → gain additional privileges
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-20 ↗

CWE-20: Improper Input Validation. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
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

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkPrivilege escalationCWE-20CISA KEV
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2021-29254Known-exploited evidence recorded

Active Directory Domain Services Elevation of Privilege Vulnerability

Official EUVD record ↗
Cyber Security Agency of Singapore · English · CSA-SB-20211117Security Bulletin 17 Nov 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 17 Nov 2021, published on 17 November 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-862Multiples vulnérabilités dans Microsoft Windows

d?id=CVE-2021-41370 Référence CVE CVE-2021-41371 https://www.cve.org/CVERecord?id=CVE-2021-41371 Référence CVE CVE-2021-41377 https://www.cve.org/CVERecord?id=CVE-2021-41377 Référence CVE CVE-2021-41378 https://www.cve.org/CVERecord?id=CVE-2021-41378 Référence CVE CVE-2021-41379 https://www.cve.org/CVERecord?id=CVE-2021-41379 Référence CVE CVE-2021-42274 https://www.cve.org/CVERecord?id=CVE-2021-42274 Référence CVE CVE-2021-42275 https://www.cve.org/CVERecord?id=CVE-2021-42275 Référence CVE CVE-2021-42276 https://www.cve.org/CVERecord?id=CVE-2021-42276 Référence CVE CVE-2021-42277 https://www.cve.org/CVERecord?id=CVE-2021-42277 Référence CVE CVE-2021-42278 https://www.cve.org/CVERecord?id=CVE-2021-42278 Référence CVE CVE-2021-42279 https://www.cve.org/CVERecord?id=CVE-2021-42279 Référence CVE CVE-2021-42280 https://www.cve.org/CVERecord?id=CVE-2021-42280 Référence CVE CVE-2021-42282 https://www.cve.org/CVERecord?id=CVE-2021-42282 Référence CVE CVE-2021-42283 https://www.cve.org/CVERecord?id=CVE-2021-42283 Référence CVE CVE-2021-42284 https://www.cve.org/CVERecord?id=CVE-2021-42284 Référence CVE CVE-2021-42285 https://www.cve.org/CVERecord?id=CVE-2021-42285 Référence CVE CVE-2021-42286 https://www.cve.org/CVERecord?id=CVE-2021-42286 Référence CVE CVE-2021-42287 https://www.cve.org/CVERecord?id=

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-004143Microsoft Windows Server における権限を昇格される脆弱性

Microsoft Windows Server には、Active Directory Domain Services に不備があるため、権限を昇格される脆弱性が存在します。 本脆弱性は、CVE-2021-42282、CVE-2021-42287、CVE-2021-42291 とは異なる脆弱性です。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-004136Microsoft Windows Server における権限を昇格される脆弱性

Microsoft Windows Server には、Active Directory Domain Services に不備があるため、権限を昇格される脆弱性が存在します。 本脆弱性は、CVE-2021-42278、CVE-2021-42282、CVE-2021-42287 とは異なる脆弱性です。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-004135Microsoft Windows Server における権限を昇格される脆弱性

Microsoft Windows Server には、Active Directory Domain Services に不備があるため、権限を昇格される脆弱性が存在します。 本脆弱性は、CVE-2021-42278、CVE-2021-42282、CVE-2021-42291 とは異なる脆弱性です。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-004130Windows Server における権限を昇格される脆弱性

Windows Server には、Active Directory Domain Services に不備があるため、権限を昇格される脆弱性が存在します。 本脆弱性は、CVE-2021-42278、CVE-2021-42287、CVE-2021-42291 とは異なる脆弱性です。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5435MS 11월 보안 위협에 따른 정기 보안 업데이트 권고

CVE-2021-42274 Windows Hyper-V Discrete Device Assignment (DDA) Denial of Service Vulnerability Visual Studio CVE-2021-42319 Visual Studio 권한 상승 취약성 Visual Studio CVE-2021-3711 OpenSSL: CVE-2021-3711 SM2 Decryption Buffer Overflow Visual Studio Code CVE-2021-42322 Visual Studio Code 권한 상승 취약성 Windows Active Directory CVE-2021-42291 Active Directory Domain Services Elevation of Privilege Vulnerability Windows Active Directory CVE-2021-42287 Active Directory Domain Services Elevation of Privilege Vulnerability Windows Active Directory CVE-2021-42282 Active Directory Domain Services Elevation of Privilege Vulnerability Windows Active Directory CVE-2021-42278 Active Directory Domain Services Elevation of Privilege Vulnerability Windows COM CVE-2021-42275 Windows용 Microsoft COM 원격 코드 실행 취약성 Windows Core Shell CVE-2021-42286 Windows Core Shell SI Host Extension Framework for Composable Shell Elevation of Privilege Vulnerability Windows Cred SSProvider Protocol CVE-2021-41366 Credential Security Support Provider Protocol (CredSSP) Elevation of Privilege Vulnerability Windows Defender CVE-2021-42298 Microsoft Defender 원격 코드 실행 취약성 Windows Desktop Bridge CVE-2021-36957 Windows 데스크톱 브리지 권한 상승 취약성 Windows Diagnostic Hub CVE-2021-42277 진단 허브 표준 수집기 권한 상승 취약성 Windows Fastfat Driver CVE-2021-41377 Windows

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 10 Nov 2021 · Last source change 19 Aug 2026, 16:27 UTC · CWE-20 · Improper Input Validation

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2021-29254
Product sourceCISA KEV
Remediation sourceCVE/CNA references
CWE sourceCISA KEV
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    6.1.7601.0 < 6.1.7601.25769; 6.0.6003.0 < 6.0.6003.21282; 6.2.9200.0 < 6.2.9200.23517; 6.3.9600.0 < 6.3.9600.20174 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    After
    Windows Server 2008 R2 Service Pack 1: 6.1.7601.0 < 6.1.7601.25769; Windows Server 2008 R2 Service Pack 1 (Server Core installation): 6.1.7601.0 < 6.1.7601.25769; Windows Server 2008 Service Pack 2: 6.0.6003.0 < 6.0.6003.21282; Windows Server 2008 Service Pack 2 (Server Core installation): 6.0.6003.0 < 6.0.6003.21282; Windows Server 2012: 6.2.9200.0 < 6.2.9200.23517; Windows Server 2012 (Server Core installation): 6.2.9200.0 < 6.2.9200.23517; Windows Server 2012 R2: 6.3.9600.0 < 6.3.9600.20174; Windows Server 2012 R2 (Server Core installation): 6.3.9600.0 < 6.3.9600.20174; Windows Server 2016: 10.0.14393.0 < 10.0.14393.4770; Windows Server 2016 (Server Core installation): 10.0.14393.0 < 10.0.14393.4770; Windows Server 2019: 10.0.17763.0 < 10.0.17763.2300; Windows Server 2019 (Server Core installation): 10.0.17763.0 < 10.0.17763.2300; Windows Server 2022: 10.0.20348.0 < 10.0.20348.350; Windows Server version 2004: 10.0.0 < 10.0.19041.1348; Windows Server version 20H2: 10.0.0 < 10.0.19042.1348 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
  3. Vendor guidanceAuthoritative vendor guidance changed: added patch: msrc.microsoft.com/CVE-2021-42278; added remediation: msrc.microsoft.com/CVE-2021-42278; removed remediation: portal.msrc.microsoft.com/CVE-2021-42278.
    Before
    patch: portal.msrc.microsoft.com/CVE-2021-42278 · remediation: portal.msrc.microsoft.com/CVE-2021-42278
    After
    patch: msrc.microsoft.com/CVE-2021-42278 · patch: portal.msrc.microsoft.com/CVE-2021-42278 · remediation: msrc.microsoft.com/CVE-2021-42278
    secure@microsoft.com ↗
  4. Vendor guidanceAuthoritative vendor guidance changed: added remediation: portal.msrc.microsoft.com/CVE-2021-42278; removed patch: msrc.microsoft.com/CVE-2021-42278; removed remediation: msrc.microsoft.com/CVE-2021-42278.
    Before
    patch: msrc.microsoft.com/CVE-2021-42278 · patch: portal.msrc.microsoft.com/CVE-2021-42278 · remediation: msrc.microsoft.com/CVE-2021-42278
    After
    patch: portal.msrc.microsoft.com/CVE-2021-42278 · remediation: portal.msrc.microsoft.com/CVE-2021-42278
    portal.msrc.microsoft.com ↗
  5. Vendor guidanceAuthoritative vendor guidance changed: added patch: msrc.microsoft.com/CVE-2021-42278; added remediation: msrc.microsoft.com/CVE-2021-42278; removed remediation: portal.msrc.microsoft.com/CVE-2021-42278.
    Before
    patch: portal.msrc.microsoft.com/CVE-2021-42278 · remediation: portal.msrc.microsoft.com/CVE-2021-42278
    After
    patch: msrc.microsoft.com/CVE-2021-42278 · patch: portal.msrc.microsoft.com/CVE-2021-42278 · remediation: msrc.microsoft.com/CVE-2021-42278
    msrc.microsoft.com ↗
  6. Affected versionsThe structured affected or fixed version information changed.
    Before
    10.0.0 < 10.0.17763.2300; 10.0.0 < 10.0.20348.350; 10.0.0 < 10.0.19041.1348; 10.0.0 < 10.0.19042.1348; 10.0.0 < 10.0.14393.4770; 6.0.0 < 6.0.6003.21282 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    After
    6.1.7601.0 < 6.1.7601.25769; 6.0.6003.0 < 6.0.6003.21282; 6.2.9200.0 < 6.2.9200.23517; 6.3.9600.0 < 6.3.9600.20174 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2021-29254↗CISA KEV record↗CVE authority or vendor reference↗Patch or update reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2021-42278 · cve.blacktree.nl