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Full vulnerability report · 2020
CVE-2020-1054High confidence

Microsoft Win32k Privilege Escalation Vulnerability

Microsoft · Win32k

7.0HighCVSS 3.1
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2022-05-03 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 54.16% 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-2020-11947

CISA KEV mirrored by ENISA

An elevation of privilege vulnerability exists in Windows when the Windows kernel-mode driver fails to properly handle objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system. The update addresses this vulnerability by correcting how the Windows kernel-mode driver handles objects in memory.

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

CISA confirms exploitation in the wild and lists 2022-05-03 as the remediation due date.

Patch available
01

What, why and how

Microsoft Win32k contains a privilege escalation vulnerability when the Windows kernel-mode driver fails to properly handle objects in memory. Successful exploitation allows an attacker to execute code in kernel mode.

What

Microsoft Win32k contains a privilege escalation vulnerability when the Windows kernel-mode driver fails to properly handle objects in memory. Successful exploitation allows an attacker to execute code in kernel mode.

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 execute code or commands in the affected security context.

What

Microsoft Win32k contains a privilege escalation vulnerability when the Windows kernel-mode driver fails to properly handle objects in memory. Successful exploitation allows an attacker to execute code in kernel mode.

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 execute code or commands in the affected security context.

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.

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 → execute code or commands in the affected security context
Attack surface
Local
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-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:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/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.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
After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
Remote code executionPrivilege 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-2020-11947Known-exploited evidence recorded

An elevation of privilege vulnerability exists in Windows when the Windows kernel-mode driver fails to properly handle objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system. The update addresses this vulnerability by correcting how the Windows kernel-mode driver handles objects in memory.

Official EUVD record ↗
Cyber Security Agency of Singapore · English · CSA-SB-20200527Security Bulletin 27 May 2020

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 27 May 2020, published on 27 May 2020. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2020-AVI-287Multiples vulnérabilités dans Microsoft Windows

tation Bulletin de sécurité Microsoft du 12 mai 2020 https://portal.msrc.microsoft.com/fr-FR/security-guidance Référence CVE CVE-2020-0909 https://www.cve.org/CVERecord?id=CVE-2020-0909 Référence CVE CVE-2020-0963 https://www.cve.org/CVERecord?id=CVE-2020-0963 Référence CVE CVE-2020-1010 https://www.cve.org/CVERecord?id=CVE-2020-1010 Référence CVE CVE-2020-1021 https://www.cve.org/CVERecord?id=CVE-2020-1021 Référence CVE CVE-2020-1028 https://www.cve.org/CVERecord?id=CVE-2020-1028 Référence CVE CVE-2020-1048 https://www.cve.org/CVERecord?id=CVE-2020-1048 Référence CVE CVE-2020-1051 https://www.cve.org/CVERecord?id=CVE-2020-1051 Référence CVE CVE-2020-1054 https://www.cve.org/CVERecord?id=CVE-2020-1054 Référence CVE CVE-2020-1055 https://www.cve.org/CVERecord?id=CVE-2020-1055 Référence CVE CVE-2020-1061 https://www.cve.org/CVERecord?id=CVE-2020-1061 Référence CVE CVE-2020-1067 https://www.cve.org/CVERecord?id=CVE-2020-1067 Référence CVE CVE-2020-1068 https://www.cve.org/CVERecord?id=CVE-2020-1068 Référence CVE CVE-2020-1070 https://www.cve.org/CVERecord?id=CVE-2020-1070 Référence CVE CVE-2020-1071 https://www.cve.org/CVERecord?id=CVE-2020-1071 Référence CVE CVE-2020-1072 https://www.cve.org/CVERecord?id=CVE-2020-1072 Référence CVE CVE-2020-1075 https://www.cve.org/CVERecord?id=CVE-2020-1075 Ré

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2020-005819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 カーネルモードドライバがメモリ内のオブジェクトの適切な処理に失敗した場合、権限を昇格される脆弱性が存在します。 ベンダは、本脆弱性を「Win32k の特権の昇格の脆弱性」として公開しています。 本脆弱性は、CVE-2020-1143 とは異なる脆弱性です。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2020-005802複数の Microsoft Windows 製品におけるメモリ破損の脆弱性

複数の Microsoft Windows 製品には、Windows カーネルモードドライバがメモリ内のオブジェクトを適切に処理しない場合、メモリ破損の脆弱性が存在します。 ベンダは、本脆弱性を「Win32k の特権の昇格の脆弱性」として公開しています。 本脆弱性は、CVE-2020-1054 とは異なる脆弱性です。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5139MS 5월 보안 위협에 따른 정기 보안 업데이트 권고

- 권한상승 취약점(CVE-2020-1010, CVE-2020-1021, CVE-2020-1048, CVE-2020-1054, CVE-2020-1056, CVE-2020-1068, CVE-2020-1070, CVE-2020-1071, CVE-2020-1077, CVE-2020-1078, CVE-2020-1079, CVE-2020-1081, CVE-2020-1082, CVE-2020-1086, CVE-2020-1087, CVE-2020-1088, CVE-2020-1090, CVE-2020-1109, CVE-2020-1110, CVE-2020-1111, CVE-2020-1112, CVE-2020-1114, CVE-2020-1121, CVE-2020-1124, CVE-2020-1125, CVE-2020-1131, CVE-2020-1132, CVE-2020-1134, CVE-2020-1135, CVE-2020-1137, CVE-2020-1138, CVE-2020-1139, CVE-2020-1140, CVE-2020-1142, CVE-2020-1143, CVE-2020-1144, CVE-2020-1149, CVE-2020-1151, CVE-2020-1154, CVE-2020-1155, CVE-2020-1156, CVE-2020-1157, CVE-2020-1158, CVE-2020-1164, CVE-2020-1165, CVE-2020-1166, CVE-2020-1184, CVE-2020-1185, CVE-2020-1186, CVE-2020-1187, CVE-2020-1188, CVE-2020-1189, CVE-2020-1190, CVE-2020-1191)

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 21 May 2020 · Last source change 19 Aug 2026, 16:33 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-2020-11947
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
    10.0.10240.0 < publication; 10.0.14393.0 < publication; 10.0.0 < publication; 10.0.17763.0 < 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 1507: 10.0.10240.0 < publication; Windows 10 Version 1607: 10.0.14393.0 < publication; Windows 10 Version 1709: 10.0.0 < publication; Windows 10 Version 1709 for 32-bit Systems: 10.0.0 < publication; Windows 10 Version 1803: 10.0.0 < publication; Windows 10 Version 1809: 10.0.17763.0 < publication, 10.0.0 < publication; Windows 10 Version 1903 for 32-bit Systems: 10.0.0 < publication; Windows 10 Version 1903 for ARM64-based Systems: 10.0.0 < publication; Windows 10 Version 1903 for x64-based Systems: 10.0.0 < publication; Windows 10 Version 1909: 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 R2 Service Pack 1: 6.1.7601.0 < publication; Windows Server 2008 R2 Service Pack 1 (Server Core installation): 6.1.7601.0 < publication; Windows Server 2008 Service Pack 2: 6.0.6003.0 < publication; Windows Server 2008 Service Pack 2 (Server Core installation): 6.0.6003.0 < publication; Windows Server 2012: 6.2.9200.0 < publication; Windows Server 2012 (Server Core installation): 6.2.9200.0 < publication; Windows Server 2012 R2: 6.3.9600.0 < publication; Windows Server 2012 R2 (Server Core installation): 6.3.9600.0 < publication; Windows Server 2016: 10.0.14393.0 < publication; Windows Server 2016 (Server Core installation): 10.0.14393.0 < publication; Windows Server 2019: 10.0.17763.0 < publication; Windows Server 2019 (Server Core installation): 10.0.17763.0 < publication; Windows Server, version 1803 (Server Core Installation): 10.0.0 < publication; Windows Server, version 1903 (Server Core installation): 10.0.0 < publication; Windows Server, version 1909 (Server Core installation): 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 ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: added patch: msrc.microsoft.com/CVE-2020-1054; added remediation: msrc.microsoft.com/CVE-2020-1054; removed remediation: portal.msrc.microsoft.com/CVE-2020-1054.
    Before
    patch: portal.msrc.microsoft.com/CVE-2020-1054 · remediation: portal.msrc.microsoft.com/CVE-2020-1054
    After
    patch: msrc.microsoft.com/CVE-2020-1054 · patch: portal.msrc.microsoft.com/CVE-2020-1054 · remediation: msrc.microsoft.com/CVE-2020-1054
    secure@microsoft.com ↗
  3. Vendor guidanceAuthoritative vendor guidance changed: added remediation: portal.msrc.microsoft.com/CVE-2020-1054; removed patch: msrc.microsoft.com/CVE-2020-1054; removed remediation: msrc.microsoft.com/CVE-2020-1054.
    Before
    patch: msrc.microsoft.com/CVE-2020-1054 · patch: portal.msrc.microsoft.com/CVE-2020-1054 · remediation: msrc.microsoft.com/CVE-2020-1054
    After
    patch: portal.msrc.microsoft.com/CVE-2020-1054 · remediation: portal.msrc.microsoft.com/CVE-2020-1054
    portal.msrc.microsoft.com ↗
  4. Vendor guidanceAuthoritative vendor guidance changed: added patch: msrc.microsoft.com/CVE-2020-1054; added remediation: msrc.microsoft.com/CVE-2020-1054; removed remediation: portal.msrc.microsoft.com/CVE-2020-1054.
    Before
    patch: portal.msrc.microsoft.com/CVE-2020-1054 · remediation: portal.msrc.microsoft.com/CVE-2020-1054
    After
    patch: msrc.microsoft.com/CVE-2020-1054 · patch: portal.msrc.microsoft.com/CVE-2020-1054 · remediation: msrc.microsoft.com/CVE-2020-1054
    msrc.microsoft.com ↗
  5. Affected versionsThe structured affected or fixed version information changed.
    Before
    10 Version 1803 for 32-bit Systems; 10 Version 1803 for x64-based Systems; 10 Version 1803 for ARM64-based Systems; 10 Version 1809 for 32-bit Systems; 10 Version 1809 for x64-based Systems; 10 Version 1809 for ARM64-based Systems; 10 Version 1709 for 32-bit Systems; 10 Version 1709 for x64-based Systems · 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
    10.0.10240.0 < publication; 10.0.14393.0 < publication; 10.0.0 < publication; 10.0.17763.0 < 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 ↗
  6. CVSS scoreCVSS score changed from 7.8 (CVSS 3.1 · NIST NVD · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) to 7.0 (CVSS 3.1 · CNA · CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C).
    Before
    7.8 (CVSS 3.1 · NIST NVD · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
    After
    7.0 (CVSS 3.1 · CNA · CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C)
    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-2020-11947↗CISA KEV record↗CVE authority or vendor reference↗Patch or update 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-2020-1054 · cve.blacktree.nl