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Full vulnerability report · 2021
CVE-2021-1694High confidence

Windows Update Stack Elevation of Privilege Vulnerability

Microsoft · Windows 10 Version 1803

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 3.25% for the current model date.

Compensating controls

  • Restrict local access and enforce least privilege on affected hosts.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Microsoft Windows 10 Version 1803 and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  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 30 daysRemediation target: Within 180 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-2021-7161

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
01

What, why and how

Windows Update Stack Elevation of Privilege Vulnerability

What

Windows Update Stack Elevation of Privilege Vulnerability

Why

The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. If successful, the issue may gain additional privileges.

What

Windows Update Stack Elevation of Privilege Vulnerability

Why

The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. 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.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

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
an adjacent network → Improper Privilege Management → gain additional privileges
Attack surface
Adjacent
Privileges required
None: unauthenticated exploitation is possible
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-269 ↗

CWE-269: Improper Privilege Management. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:A/AC:H/PR:N/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.

AVAdjacentAttack vector: The attacker must be on an adjacent or logically close network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing 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.
UnauthenticatedPrivilege escalationCWE-269
A

Official authority intelligence

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

Cyber Security Agency of Singapore · English · CSA-SB-20210113Security Bulletin 13 Jan 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 13 Jan 2021, published on 13 January 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-027Multiples vulnérabilités dans Microsoft Windows

.cve.org/CVERecord?id=CVE-2021-1685 Référence CVE CVE-2021-1686 https://www.cve.org/CVERecord?id=CVE-2021-1686 Référence CVE CVE-2021-1687 https://www.cve.org/CVERecord?id=CVE-2021-1687 Référence CVE CVE-2021-1688 https://www.cve.org/CVERecord?id=CVE-2021-1688 Référence CVE CVE-2021-1689 https://www.cve.org/CVERecord?id=CVE-2021-1689 Référence CVE CVE-2021-1690 https://www.cve.org/CVERecord?id=CVE-2021-1690 Référence CVE CVE-2021-1691 https://www.cve.org/CVERecord?id=CVE-2021-1691 Référence CVE CVE-2021-1692 https://www.cve.org/CVERecord?id=CVE-2021-1692 Référence CVE CVE-2021-1693 https://www.cve.org/CVERecord?id=CVE-2021-1693 Référence CVE CVE-2021-1694 https://www.cve.org/CVERecord?id=CVE-2021-1694 Référence CVE CVE-2021-1695 https://www.cve.org/CVERecord?id=CVE-2021-1695 Référence CVE CVE-2021-1696 https://www.cve.org/CVERecord?id=CVE-2021-1696 Référence CVE CVE-2021-1697 https://www.cve.org/CVERecord?id=CVE-2021-1697 Référence CVE CVE-2021-1699 https://www.cve.org/CVERecord?id=CVE-2021-1699 Référence CVE CVE-2021-1700 https://www.cve.org/CVERecord?id=CVE-2021-1700 Référence CVE CVE-2021-1701 https://www.cve.org/CVERecord?id=CVE-2021-1701 Référence CVE CVE-2021-1702 https://www.cve.org/CVERecord?id=CVE-2021-1702 Référence CVE CVE-2021-1703 https://www.cve.org/CVERecord?id=CVE-2021-1703 Ré

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-001072複数の Microsoft Windows 製品における権限を昇格される脆弱性

複数の Microsoft Windows 製品には、Windows Update スタックに不備があるため、権限を昇格される脆弱性が存在します。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5257MS 1월 보안 위협에 따른 정기 보안 업데이트 권고

-2021-1674 Windows 원격 데스크톱 프로토콜 핵심 보안 기능 우회 취약성 CVE-2021-1669 Windows 원격 데스크톱 보안 기능 우회 취약성 Windows Remote Procedure Call Runtime CVE-2021-1701 원격 프로시저 호출 런타임 원격 코드 실행 취약성 CVE-2021-1700 원격 프로시저 호출 런타임 원격 코드 실행 취약성 CVE-2021-1673 원격 프로시저 호출 런타임 원격 코드 실행 취약성 CVE-2021-1671 원격 프로시저 호출 런타임 원격 코드 실행 취약성 CVE-2021-1667 원격 프로시저 호출 런타임 원격 코드 실행 취약성 CVE-2021-1666 원격 프로시저 호출 런타임 원격 코드 실행 취약성 CVE-2021-1664 원격 프로시저 호출 런타임 원격 코드 실행 취약성 CVE-2021-1660 원격 프로시저 호출 런타임 원격 코드 실행 취약성 CVE-2021-1658 원격 프로시저 호출 런타임 원격 코드 실행 취약성 Windows splwow64 CVE-2021-1648 Microsoft splwow64 권한 상승 취약성 Windows TPM Device Driver CVE-2021-1656 TPM 장치 드라이버 정보 유출 취약성 Windows Update Stack CVE-2021-1694 Windows 업데이트 스택 권한 상승 취약성 Windows WalletService CVE-2021-1690 Windows WalletService 권한 상승 취약성 CVE-2021-1687 Windows WalletService 권한 상승 취약성 CVE-2021-1686 Windows WalletService 권한 상승 취약성 CVE-2021-1681 Windows WalletService 권한 상승 취약성 ##### □ 작성 : 침해사고분석단 취약점분석팀

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.
Fix not verified
Affected
  • Windows 10 Version 1803: 10.0.0 < publication
  • Windows 10 Version 1809: 10.0.0 < publication
  • Windows Server 2019: 10.0.0 < publication
  • Windows Server 2019 (Server Core installation): 10.0.0 < publication
  • Windows 10 Version 1909: 10.0.0 < publication
  • Windows Server, version 1909 (Server Core installation): 10.0.0 < publication
  • Windows 10 Version 2004: 10.0.0 < publication
  • Windows Server version 2004: 10.0.0 < publication
  • Windows 10 Version 1507: 10.0.0 < publication
  • Windows 10 Version 1607: 10.0.0 < publication
  • Windows Server 2016: 10.0.0 < publication
  • Windows Server 2016 (Server Core installation): 10.0.0 < publication
  • Windows 7: 6.1.0 < publication
  • Windows 7 Service Pack 1: 6.1.0 < publication
  • Windows 8.1: 6.3.0 < publication
  • Windows Server 2008 Service Pack 2: 6.0.0 < publication
  • Windows Server 2008 Service Pack 2 (Server Core installation): 6.0.0 < publication
  • Windows Server 2008 Service Pack 2: 6.0.0 < publication
  • Windows Server 2008 R2 Service Pack 1: 6.1.0 < publication
  • Windows Server 2008 R2 Service Pack 1 (Server Core installation): 6.0.0 < publication
  • Windows Server 2012: 6.2.0 < publication
  • Windows Server 2012 (Server Core installation): 6.2.0 < publication
  • Windows Server 2012 R2: 6.3.0 < publication
  • Windows Server 2012 R2 (Server Core installation): 6.3.0 < publication
  • Windows 10 Version 20H2: 10.0.0 < publication
  • Windows Server version 20H2: 10.0.0 < publication
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 12 Jan 2021 · Last source change 8 Oct 2024, 16:17 UTC · CWE-269 · Improper Privilege Management

CVE recordCVE.org · 5.1
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-2021-7161
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceNIST NVD
NVD statusNVD modified after enrichment

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

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2021-7161↗CVE authority or vendor 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-2021-1694 · cve.blacktree.nl