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Full vulnerability report · 2021
CVE-2021-1732High confidence

Microsoft Win32k Privilege Escalation Vulnerability

Microsoft · Win32k

7.8HighCVSS 3.1
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2021-11-17 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 3 Nov 2021

Evidence used

  • CISA confirms exploitation in the wild.
  • A structured source references public exploit or proof-of-concept material.
  • Exploitation requires an existing local or physical foothold with privileges.
  • EPSS is 78.38% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Microsoft Win32k 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-2021-7196

CISA KEV mirrored by ENISA

Windows Win32k Elevation of Privilege Vulnerability

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 3 Nov 2021. Evidence sources: cisa_kev.
ENISA score
7.8 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2021-11-17 as the remediation due date.

Patch available
01

What, why and how

Microsoft Win32k contains an unspecified vulnerability that allows for privilege escalation.

What

Microsoft Win32k contains an unspecified vulnerability that allows for privilege escalation.

Why

A bounds error lets data be written beyond the intended memory region, potentially corrupting control data.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may gain additional privileges.

What

Microsoft Win32k contains an unspecified vulnerability that allows for privilege escalation.

Why

A bounds error lets data be written beyond the intended memory region, potentially corrupting control data.

How

An attacker operating through local access 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 2021-11-03. 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.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
local access → Out-of-bounds Write → gain additional privileges
Attack surface
Local
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
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-787 ↗

CWE-787: Out-of-bounds Write. The product writes data past the end, or before the beginning, of the intended buffer.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

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

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.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
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
Privilege escalationCWE-787CISA KEVPublic exploit reference
A

Official authority intelligence

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

ENISA EUVD · EUVD-2021-7196Known-exploited evidence recorded

Windows Win32k Elevation of Privilege Vulnerability

Official EUVD record ↗
Canadian Centre for Cyber Security · English · AV21-073Microsoft security advisory – February 2021 monthly rollup

On 9 February 2021 Microsoft published Security Updates to address vulnerabilities in multiple products. Included were critical updates for the following: Included in this update is the default enablement of Domain Controller enforcement mode, which blocks insecure NRPC connections from non-compliant devices.  This update also addresses a vulnerability in Windows Win32k which may result in an escalation of privilege resulting in full system compromise. Microsoft has confirmed this vulnerability has been detected in the wild.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20210303Security Bulletin 03 Mar 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 03 Mar 2021, published on 3 March 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-105Multiples vulnérabilités dans Microsoft Windows

ion de privilèges. Solution Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation). Documentation Bulletin de sécurité Microsoft du 09 février 2021 https://portal.msrc.microsoft.com/fr-FR/security-guidance Référence CVE CVE-2020-17162 https://www.cve.org/CVERecord?id=CVE-2020-17162 Référence CVE CVE-2021-1698 https://www.cve.org/CVERecord?id=CVE-2021-1698 Référence CVE CVE-2021-1722 https://www.cve.org/CVERecord?id=CVE-2021-1722 Référence CVE CVE-2021-1727 https://www.cve.org/CVERecord?id=CVE-2021-1727 Référence CVE CVE-2021-1731 https://www.cve.org/CVERecord?id=CVE-2021-1731 Référence CVE CVE-2021-1732 https://www.cve.org/CVERecord?id=CVE-2021-1732 Référence CVE CVE-2021-1734 https://www.cve.org/CVERecord?id=CVE-2021-1734 Référence CVE CVE-2021-24074 https://www.cve.org/CVERecord?id=CVE-2021-24074 Référence CVE CVE-2021-24075 https://www.cve.org/CVERecord?id=CVE-2021-24075 Référence CVE CVE-2021-24076 https://www.cve.org/CVERecord?id=CVE-2021-24076 Référence CVE CVE-2021-24077 https://www.cve.org/CVERecord?id=CVE-2021-24077 Référence CVE CVE-2021-24078 https://www.cve.org/CVERecord?id=CVE-2021-24078 Référence CVE CVE-2021-24079 https://www.cve.org/CVERecord?id=CVE-2021-24079 Référence CVE CVE-2021-24080 https://www.cve.org/CVERecord?id=CVE

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-001163Windows 10 および Windows Server における権限を昇格される脆弱性

Windows 10 および Windows Server には、Windows Win32k 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-2021-1698 とは異なる脆弱性です。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-001155Microsoft Windows 10 および Windows Server における権限を昇格される脆弱性

Microsoft Windows 10 および Windows Server には、Windows Win32k 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-2021-1732 とは異なる脆弱性です。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5271MS 2월 보안 위협에 따른 정기 보안 업데이트 권고

Extension Remote Code Execution Vulnerability Windows Address Book CVE-2021-24083 Windows 주소록 원격 코드 실행 취약성 Windows Backup Engine CVE-2021-24079 Windows 백업 엔진 정보 유출 취약성 Windows Console Driver CVE-2021-24098 Windows 콘솔 드라이버 서비스 거부 취약성 Windows Defender CVE-2021-24092 Microsoft Defender 권한 상승 취약성 Windows DirectX CVE-2021-24106 Windows DirectX 정보 유출 취약성 Windows Event Tracing CVE-2021-24103 Windows 이벤트 추적 권한 상승 취약성 Windows Event Tracing CVE-2021-24102 Windows 이벤트 추적 권한 상승 취약성 Windows Hyper-V CVE-2021-1692 Hyper-V 서비스 거부 취약성 Windows Installer CVE-2021-1727 Windows Installer 권한 상승 취약성 Windows Kernel CVE-2021-24096 Windows 커널 권한 상승 취약성 Windows Kernel CVE-2021-1732 Windows Win32k 권한 상승 취약성 Windows Kernel CVE-2021-1698 Windows Win32k 권한 상승 취약성 Windows Mobile Device Management CVE-2021-24084 Windows 모바일 장치 관리 정보 유출 취약성 Windows Network File System CVE-2021-24075 Windows 네트워크 파일 시스템 서비스 거부 취약성 Windows PFX Encryption CVE-2021-1731 PFX 암호화 보안 기능 우회 취약성 Windows PKU2U CVE-2021-25195 Windows PKU2U 권한 상승 취약성 Windows PowerShell CVE-2021-24082 Microsoft PowerShell 유틸리티 모듈 WDAC 보안 기능 우회 취약성 Windows Print Spooler Components CVE-2021-24088 Windows 로컬 스풀러 원격 코드 실행 취약성 Windows Remote Procedure Call CVE-2021-1734 Windows 원격 프로시저 호출 정보 유출 취약성 Windows TCP/IP CVE-2021-24094 Windows TCP/IP 원격 코드 실행 취약성 Windows TCP/IP CVE-20

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. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 25 Feb 2021 · Last source change 12 Aug 2026, 03:55 UTC · CWE-787 · Out-of-bounds Write

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-2021-7196
Product sourceCISA KEV
Remediation sourceCVE/CNA references
CWE sourceCISA ADP
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. Affected versionsThe structured affected or fixed version information changed.
    Before
    10.0.0 < publication · 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 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 20H2: 10.0.0 < publication; Windows Server version 20H2: 10.0.0 < publication · 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-2021-7196↗CISA KEV record↗CVE authority or vendor reference↗Public exploit reference↗Public exploit 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-2021-1732 · cve.blacktree.nl