CVE-2026-45657: Windows Kernel Remote Code Execution Vulnerability

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 15.5% 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-416

Description

Use after free in Windows Kernel allows an unauthorized attacker to execute code over a network.

Affected products

Microsoft Windows 11: before 10.0.22631.7219 — fixed in 10.0.22631.7219
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 2022: before 10.0.20348.5256 — fixed in 10.0.20348.5256
Microsoft Windows Server 2025: before 10.0.26100.32995 — fixed in 10.0.26100.32995
Microsoft Windows 11: from 10.0.22631.0 before 10.0.22631.7219 — fixed in 10.0.22631.7219
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 2022: from 10.0.20348.0 before 10.0.20348.5256 — fixed in 10.0.20348.5256
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 10.0.22631.7219; 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 2022 10.0.20348.5256; Microsoft Windows Server 2025 10.0.26100.32995; Microsoft Windows 11 10.0.22631.7219; 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 2022 10.0.20348.5256; Microsoft Windows Server 2025 10.0.26100.32995. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45657

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