CVE-2026-62877: Windows Win32k Elevation of Privilege Vulnerability

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-11 · updated 2026-10-30
Weakness: CWE-121

Description

Stack-based buffer overflow in Windows Win32K allows an authorized attacker to elevate privileges locally.

Affected products

Microsoft Windows 10 1607: before 10.0.14393.9418 — fixed in 10.0.14393.9418
Microsoft Windows 10: before 10.0.17763.9115 — fixed in 10.0.17763.9115
Microsoft Windows 10: before 10.0.19044.7663 — fixed in 10.0.19044.7663
Microsoft Windows 10: before 10.0.19045.7663 — fixed in 10.0.19045.7663
Microsoft Windows 11: before 10.0.22631.7517 — fixed in 10.0.22631.7517
Microsoft Windows 11: before 10.0.26100.9106 — fixed in 10.0.26100.9106
Microsoft Windows 11 25H2: before 10.0.26200.9106 — fixed in 10.0.26200.9106
Microsoft Windows 11 version 26H1: before 10.0.28000.2704 — fixed in 10.0.28000.2704
Microsoft Windows Server 2012: r2 (and their updates)
Microsoft Windows Server 2016: before 10.0.14393.9418 — fixed in 10.0.14393.9418
Microsoft Windows Server 2019: before 10.0.17763.9115 — fixed in 10.0.17763.9115
Microsoft Windows Server 2022: before 10.0.20348.5440 — fixed in 10.0.20348.5440
Microsoft Windows Server 2025: before 10.0.26100.33222 — fixed in 10.0.26100.33222
Microsoft Office 365 for Mac: from 1.0.0 before 16.112.26090911 — fixed in 16.112.26090911
Microsoft Office for Android: from 16.0.1 before 16.0.20430.20000 — fixed in 16.0.20430.20000
Microsoft Office LTSC for Mac 2024: from 16.0.0 before 16.112.26090911 — fixed in 16.112.26090911
Microsoft Office LTSC for Mac 2021: from 16.0.1 before 16.112.26090911 — fixed in 16.112.26090911

How to fix

Upgrade to a fixed version: Microsoft Windows 10 1607 10.0.14393.9418; Microsoft Windows 10 10.0.17763.9115; Microsoft Windows 10 10.0.19044.7663; Microsoft Windows 10 10.0.19045.7663; Microsoft Windows 11 10.0.22631.7517; Microsoft Windows 11 10.0.26100.9106; Microsoft Windows 11 25H2 10.0.26200.9106; Microsoft Windows 11 version 26H1 10.0.28000.2704; Microsoft Windows Server 2016 10.0.14393.9418; Microsoft Windows Server 2019 10.0.17763.9115; Microsoft Windows Server 2022 10.0.20348.5440; Microsoft Windows Server 2025 10.0.26100.33222. Check the vendor advisory for mitigations.

In the news

CVE-2026-62877 Windows Win32k Elevation of Privilege Vulnerability

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62877

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