CVE-2021-26863

highpriority · track · 33EPSS 0.119 · 96 %ileEURUUS

grimoire priorityP1 · Urgent

Exploitable?

—

no known exploitation

Likely / severe?

11.9% (96th) EPSS

CVSS 7.2 · high

Is it mine?

67 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · fstec_bdu · msrc_csaf

EPSS · scored 2026-10-28

Windows Win32k Elevation of Privilege Vulnerability

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

FixedWindows 10 Version 1803 for 32-bit Systemsmsrc_csaf
10.0.17134.2087:Security Update:https://support.microsoft.com/help/5000809
https://support.microsoft.com/help/5000809
FixedWindows 10 Version 1803 for ARM64-based Systemsmsrc_csaf
10.0.17134.2087:Security Update:https://support.microsoft.com/help/5000809
https://support.microsoft.com/help/5000809
FixedWindows 10 Version 1803 for x64-based Systemsmsrc_csaf
10.0.17134.2087:Security Update:https://support.microsoft.com/help/5000809
https://support.microsoft.com/help/5000809
FixedWindows 10 Version 1809 for 32-bit Systemsmsrc_csaf
10.0.17763.1817:Security Update:https://support.microsoft.com/help/5000822
https://support.microsoft.com/help/5000822
FixedWindows 10 Version 1809 for ARM64-based Systemsmsrc_csaf
10.0.17763.1817:Security Update:https://support.microsoft.com/help/5000822
https://support.microsoft.com/help/5000822
FixedWindows 10 Version 1809 for x64-based Systemsmsrc_csaf
10.0.17763.1817:Security Update:https://support.microsoft.com/help/5000822
https://support.microsoft.com/help/5000822
FixedWindows 10 Version 1909 for 32-bit Systemsmsrc_csaf
10.0.18363.1440:Security Update:https://support.microsoft.com/help/5000808
https://support.microsoft.com/help/5000808
FixedWindows 10 Version 1909 for ARM64-based Systemsmsrc_csaf
10.0.18363.1440:Security Update:https://support.microsoft.com/help/5000808
https://support.microsoft.com/help/5000808
FixedWindows 10 Version 1909 for x64-based Systemsmsrc_csaf
10.0.18363.1440:Security Update:https://support.microsoft.com/help/5000808
https://support.microsoft.com/help/5000808
FixedWindows 10 Version 2004 for 32-bit Systemsmsrc_csaf
10.0.19043.867:Security Update:https://support.microsoft.com/help/5000802
https://support.microsoft.com/help/5000802
FixedWindows 10 Version 2004 for ARM64-based Systemsmsrc_csaf
10.0.19043.867:Security Update:https://support.microsoft.com/help/5000802
https://support.microsoft.com/help/5000802
FixedWindows 10 Version 2004 for x64-based Systemsmsrc_csaf
10.0.19043.867:Security Update:https://support.microsoft.com/help/5000802
https://support.microsoft.com/help/5000802
FixedWindows 10 Version 20H2 for 32-bit Systemsmsrc_csaf
10.0.19043.867:Security Update:https://support.microsoft.com/help/5000802
https://support.microsoft.com/help/5000802
FixedWindows 10 Version 20H2 for ARM64-based Systemsmsrc_csaf
10.0.19043.867:Security Update:https://support.microsoft.com/help/5000802
https://support.microsoft.com/help/5000802
FixedWindows Server 2019msrc_csaf
10.0.17763.1817:Security Update:https://support.microsoft.com/help/5000822
https://support.microsoft.com/help/5000822
FixedWindows Server 2019 (Server Core installation)msrc_csaf
10.0.17763.1817:Security Update:https://support.microsoft.com/help/5000822
https://support.microsoft.com/help/5000822
FixedWindows Server, version 1909 (Server Core installation)msrc_csaf
10.0.18363.1440:Security Update:https://support.microsoft.com/help/5000808
https://support.microsoft.com/help/5000808
FixedWindows Server, version 2004 (Server Core installation)msrc_csaf
10.0.19043.867:Security Update:https://support.microsoft.com/help/5000802
https://support.microsoft.com/help/5000802
FixedWindows Server, version 20H2 (Server Core Installation)msrc_csaf
10.0.19043.867:Security Update:https://support.microsoft.com/help/5000802
https://support.microsoft.com/help/5000802

cvss

Technical severity, 0–10. One row per scoring source.

7.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.1–7.8

v2.07.2highAV:L/AC:L/Au:N/C:C/I:C/A:Cprimary · NVD / NIST USexploitability 3.9 · impact 10

v2.06.1mediumAV:L/AC:L/Au:N/C:C/I:C/A:C/E:Usecondary · CVSS-BT (t0sche)

v3.17.8highAV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.17highCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · secure@microsoft.com USexploitability 1 · impact 5.9

v3.17highCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:Csecondary · Microsoft Security Response Center US

v3.17highCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:Csecondary · ENISA EU

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · NVD / NIST USexploitability 1.8 · impact 5.9

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-269USprimaryCWE-269US

affected products (67)

Products and version ranges known to be affected.

Microsoft Windows 10 Version 180310.0.0 → publicationenisa_euvdEU
Microsoft Windows 10 Version 180910.0.0 → publicationenisa_euvdEU
Microsoft Windows 10 Version 190910.0.0 → publicationenisa_euvdEU
Microsoft Windows 10 Version 200410.0.0 → publicationenisa_euvdEU
Microsoft Windows 10 Version 20H210.0.0 → publicationenisa_euvdEU
Microsoft Windows Server 201910.0.0 → publicationenisa_euvdEU
Microsoft Windows Server 2019 (Server Core installation)10.0.0 → publicationenisa_euvdEU
Microsoft Windows Server version 200410.0.0 → publicationenisa_euvdEU
Microsoft Windows Server version 20H210.0.0 → publicationenisa_euvdEU
Microsoft Windows Server, version 1909 (Server Core installation)10.0.0 → publicationenisa_euvdEU
Microsoft Corp Windows 10 1803all versionsfstec_bduRU
Microsoft Corp Windows 10 1809all versionsfstec_bduRU
Microsoft Corp Windows 10 1909all versionsfstec_bduRU
Microsoft Corp Windows 10 2004all versionsfstec_bduRU
Microsoft Corp Windows 10 20H2all versionsfstec_bduRU
Microsoft Corp Windows Server 1909 (Server Core Installation)all versionsfstec_bduRU
Microsoft Corp Windows Server 2004 (Server Core Installation)all versionsfstec_bduRU
Microsoft Corp Windows Server 2019all versionsfstec_bduRU
Microsoft Corp Windows Server 2019 (Server Core installation)all versionsfstec_bduRU
Microsoft Corp Windows Server 20H2 (Server Core Installation)all versionsfstec_bduRU

showing 20 of 67

advisories (1)

Vendor and ecosystem advisories describing this.

msrc_CVE-2021-26863Windows Win32k Elevation of Privilege Vulnerability2021-03-09csaf · msrc_csafUS
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu msrc_csaf NVD CVE.org MITRE

published 2021-03-11modified 2026-08-19

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+6666 more

references (9)

External citations — patches, advisories, analysis.

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