CVE-2026-42910: Windows Hotpatch Monitoring Service 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: 2026-06-09 · updated 2026-09-24
Weakness: CWE-787

Description

Out-of-bounds write in Windows Hotpatch Monitoring Service allows an authorized attacker to elevate privileges locally.

Affected products

Microsoft Windows 11: before 10.0.26100.8655 — fixed in 10.0.26100.8655
Microsoft Windows 11 25H2: before 10.0.26200.8655 — fixed in 10.0.26200.8655
Microsoft Windows 11 version 26H1: before 10.0.28000.2269 — fixed in 10.0.28000.2269
Microsoft Windows Server 2025: before 10.0.26100.32995 — fixed in 10.0.26100.32995
Microsoft Windows 11: from 10.0.26100.0 before 10.0.26100.8655 — fixed in 10.0.26100.8655
Microsoft Windows 11 25H2: from 10.0.26200.0 before 10.0.26200.8655 — fixed in 10.0.26200.8655
Microsoft Windows 11 version 26H1: from 10.0.28000.0 before 10.0.28000.2269 — fixed in 10.0.28000.2269
Microsoft Windows Server 2025: from 10.0.26100.0 before 10.0.26100.32995 — fixed in 10.0.26100.32995

How to fix

Upgrade to a fixed version: Microsoft Windows 11 10.0.26100.8655; Microsoft Windows 11 25H2 10.0.26200.8655; Microsoft Windows 11 version 26H1 10.0.28000.2269; Microsoft Windows Server 2025 10.0.26100.32995; Microsoft Windows 11 10.0.26100.8655; Microsoft Windows 11 25H2 10.0.26200.8655; Microsoft Windows 11 version 26H1 10.0.28000.2269; Microsoft Windows Server 2025 10.0.26100.32995. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42910

Get alerted when CVE-2026-42910 or the next vulnerability affects your stack