Check Point Advisories

Microsoft Windows Heap Overflow (CVE-2026-20840; CVE-2026-20922)

Vulnerability
Protection

Check Point Reference:	CPAI-2026-8117
Date Published:	22 Jun 2026
Severity:	High
Last Updated:	Monday 29 June, 2026
Source:
Industry Reference:	CVE-2026-20840 CVE-2026-20922
Protection Provided by:	Security Gateway R81, R80
Who is Vulnerable?	Microsoft Windows 10 1607 x64 prior to 10.0.14393.8783 Microsoft Windows 10 1607 x86 prior to 10.0.14393.8783 Microsoft Windows 10 1809 x64 prior to 10.0.17763.8276 Microsoft Windows 10 1809 x86 prior to 10.0.17763.8276 Microsoft Windows 10 21H2 prior to 10.0.19044.6809 Microsoft Windows 10 22H2 prior to 10.0.19045.6809 Microsoft Windows 11 23H2 prior to 10.0.22631.6491 Microsoft Windows 11 24H2 prior to 10.0.26100.7623 Microsoft Windows 11 25H2 prior to 10.0.26200.7623 Microsoft Windows Server 2008 SP2 x64 Microsoft Windows Server 2008 SP2 x86 Microsoft Windows Server 2008 R2 SP1 x64 Microsoft Windows Server 2012 Microsoft Windows Server 2012 R2 Microsoft Windows Server 2016 prior to 10.0.14393.8783 Microsoft Windows Server 2019 prior to 10.0.17763.8276 Microsoft Windows Server 2022 prior to 10.0.20348.4648 Microsoft Windows Server 2022 23H2 prior to 10.0.25398.2092 Microsoft Windows Server 2025 prior to 10.0.26100.32230
Vulnerability Description	A heap overflow vulnerability exists in Microsoft Windows. Successful exploitation of this vulnerability could allow a remote attacker to execute arbitrary code on the affected system or cause application crashes.

Protection Overview

This protection detects attempts to exploit this vulnerability.

In order for the protection to be activated, update your Security Gateway product to the latest IPS update. For information on how to update IPS, go to SBP-2006-05, click on Protection tab and select the version of your choice.

Security Gateway R80

In the IPS tab, click Protections and find the Microsoft Windows Heap Overflow protection using the Search tool and Edit the protection's settings.
Install policy on all Security Gateways.

This protection's log will contain the following information:

Attack Name: Windows SMB Protection Violation.
Attack Information: Microsoft Windows Heap Overflow