Zscaler protects against 12 new vulnerabilities for Windows

Zscaler, working with Microsoft through their MAPP program, has proactively deployed protection for the following 12 vulnerabilities included in the May 2026 Microsoft security bulletins. Zscaler will continue to monitor exploits associated with all vulnerabilities in the May release and deploy additional protections, as necessary.

CVE-2026-33835 – Windows Cloud Files Mini Filter Driver Elevation of Privilege Vulnerability

Severity: Important

Subscriptions Required

• Advanced Cloud Sandbox
• Advanced Threat Protection

Affected Software

• Windows 11 Version 26H1 for ARM64-based Systems
• Windows 11 version 26H1 for x64-based Systems
• Windows Server 2025
• Windows 11 Version 23H2 for x64-based Systems
• Windows 11 Version 24H2 for x64-based Systems
• Windows Server 2022, 23H2 Edition (Server Core installation)
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 23H2 for ARM64-based Systems
• Windows 11 Version 25H2 for ARM64-based Systems
• Windows Server 2025 (Server Core installation)
• Windows 10 Version 22H2 for 32-bit Systems
• Windows 10 Version 22H2 for ARM64-based Systems
• Windows 10 Version 22H2 for x64-based Systems
• Windows 10 Version 21H2 for x64-based Systems
• Windows 10 Version 21H2 for 32-bit Systems
• Windows 10 Version 21H2 for ARM64-based Systems
• Windows Server 2019 (Server Core installation)
• Windows Server 2022 (Server Core installation)
• Windows 10 Version 1809 for x64-based Systems
• Windows 10 Version 1809 for 32-bit Systems
• Windows Server 2022
• Windows Server 2019

CVE-2026-33837 – Windows TCP/IP Local Elevation of Privilege Vulnerability

Severity: Important

Subscriptions Required

• Advanced Threat Protection
• Advanced Cloud Sandbox

Affected Software

• Windows Server 2012 R2 (Server Core installation)
• Windows Server 2012 R2
• Windows Server 2012 (Server Core installation)
• Windows Server 2012
• Windows Server 2016 (Server Core installation)
• Windows Server 2016
• Windows 10 Version 1607 for x64-based Systems
• Windows 10 Version 1607 for 32-bit Systems
• Windows 11 Version 26H1 for ARM64-based Systems
• Windows 11 version 26H1 for x64-based Systems
• Windows Server 2025
• Windows 11 Version 24H2 for x64-based Systems
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows Server 2022, 23H2 Edition (Server Core installation)
• Windows 11 Version 23H2 for x64-based Systems
• Windows 11 Version 23H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 25H2 for ARM64-based Systems
• Windows Server 2025 (Server Core installation)
• Windows 10 Version 22H2 for 32-bit Systems
• Windows 10 Version 22H2 for ARM64-based Systems
• Windows 10 Version 22H2 for x64-based Systems
• Windows 10 Version 21H2 for x64-based Systems
• Windows 10 Version 21H2 for ARM64-based Systems
• Windows 10 Version 21H2 for 32-bit Systems
• Windows Server 2022 (Server Core installation)
• Windows Server 2022
• Windows Server 2019 (Server Core installation)
• Windows Server 2019
• Windows 10 Version 1809 for x64-based Systems
• Windows 10 Version 1809 for 32-bit Systems

CVE-2026-33840 – Win32k Elevation of Privilege Vulnerability

Severity: Important

Subscriptions Required

• Advanced Cloud Sandbox
• Advanced Threat Protection

Affected Software

• Windows 11 Version 26H1 for ARM64-based Systems
• Windows 11 version 26H1 for x64-based Systems
• Windows Server 2025
• Windows 11 Version 24H2 for x64-based Systems
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 25H2 for ARM64-based Systems
• Windows Server 2025 (Server Core installation)

CVE-2026-33841 – Windows Kernel Elevation of Privilege Vulnerability

Severity: Important

Subscriptions Required

• Advanced Cloud Sandbox
• Advanced Threat Protection

Affected Software

• Windows 11 Version 26H1 for x64-based Systems
• Windows 11 Version 26H1 for ARM64-based Systems
• Windows Server 2025
• Windows 11 Version 24H2 for x64-based Systems
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows Server 2022, 23H2 Edition (Server Core installation)
• Windows 11 Version 23H2 for x64-based Systems
• Windows 11 Version 23H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 25H2 for ARM64-based Systems
• Windows Server 2025 (Server Core installation)
• Windows 10 Version 22H2 for 32-bit Systems
• Windows 10 Version 22H2 for ARM64-based Systems
• Windows 10 Version 22H2 for x64-based Systems
• Windows 10 Version 21H2 for x64-based Systems
• Windows 10 Version 21H2 for ARM64-based Systems
• Windows 10 Version 21H2 for 32-bit Systems
• Windows Server 2022 (Server Core installation)
• Windows Server 2022

CVE-2026-35416 – Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Severity: Important

Subscriptions Required

• Advanced Threat Protection
• Advanced Cloud Sandbox

Affected Software

• Windows Server 2025 (Server Core installation)
• Windows 10 Version 22H2 for 32-bit Systems
• Windows 10 Version 22H2 for ARM64-based Systems
• Windows 10 Version 22H2 for x64-based Systems
• Windows 10 Version 21H2 for x64-based Systems
• Windows 10 Version 21H2 for ARM64-based Systems
• Windows 10 Version 21H2 for 32-bit Systems
• Windows Server 2022 (Server Core installation)
• Windows Server 2022
• Windows Server 2019 (Server Core installation)
• Windows Server 2019
• Windows 10 Version 1809 for x64-based Systems
• Windows 10 Version 1809 for 32-bit Systems
• Windows Server 2012 R2 (Server Core installation)
• Windows Server 2012 R2
• Windows Server 2012 (Server Core installation)
• Windows Server 2012
• Windows Server 2016 (Server Core installation)
• Windows Server 2016
• Windows 10 Version 1607 for x64-based Systems
• Windows 10 Version 1607 for 32-bit Systems
• Windows 11 Version 26H1 for ARM64-based Systems
• Windows 11 version 26H1 for x64-based Systems
• Windows Server 2025
• Windows 11 Version 24H2 for x64-based Systems
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows Server 2022, 23H2 Edition (Server Core installation)
• Windows 11 Version 23H2 for x64-based Systems
• Windows 11 Version 23H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 25H2 for ARM64-based Systems

CVE-2026-35417 – Windows Win32k Elevation of Privilege Vulnerability

Severity: Important

Subscriptions Required

• Advanced Threat Protection
• Advanced Cloud Sandbox

Affected Software

• Windows 11 Version 26H1 for ARM64-based Systems
• Windows 11 version 26H1 for x64-based Systems
• Windows Server 2025
• Windows 11 Version 24H2 for x64-based Systems
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows Server 2022, 23H2 Edition (Server Core installation)
• Windows 11 Version 23H2 for x64-based Systems
• Windows 11 Version 23H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 25H2 for ARM64-based Systems
• Windows Server 2025 (Server Core installation)
• Windows 10 Version 22H2 for 32-bit Systems
• Windows 10 Version 22H2 for ARM64-based Systems
• Windows 10 Version 22H2 for x64-based Systems
• Windows 10 Version 21H2 for x64-based Systems
• Windows 10 Version 21H2 for ARM64-based Systems
• Windows 10 Version 21H2 for 32-bit Systems
• Windows Server 2022 (Server Core installation)
• Windows Server 2022
• Windows Server 2019 (Server Core installation)
• Windows Server 2019
• Windows 10 Version 1809 for x64-based Systems
• Windows 10 Version 1809 for 32-bit Systems

CVE-2026-40361 – Microsoft Word Remote Code Execution Vulnerability

Severity: Critical

Subscriptions Required

• Advanced Threat Protection
• Advanced Cloud Sandbox

Affected Software

• Microsoft Word 2016 (64-bit edition)
• Microsoft Word 2016 (32-bit edition)
• Microsoft Office LTSC for Mac 2024
• Microsoft Office LTSC 2024 for 64-bit editions
• Microsoft Office LTSC 2024 for 32-bit editions
• Microsoft Office LTSC 2021 for 32-bit editions
• Microsoft Office LTSC 2021 for 64-bit editions
• Microsoft Office LTSC for Mac 2021
• Microsoft 365 Apps for Enterprise for 64-bit Systems
• Microsoft 365 Apps for Enterprise for 32-bit Systems
• Microsoft Office 2019 for 64-bit editions
• Microsoft Office 2019 for 32-bit edition

CVE-2026-40364 – Microsoft Word Remote Code Execution Vulnerability

Severity: Critical

Subscriptions Required

• Advanced Threat Protection
• Advanced Cloud Sandbox

Affected Software

• Microsoft Word 2016 (64-bit edition)
• Microsoft Word 2016 (32-bit edition)
• Microsoft Office LTSC for Mac 2024
• Microsoft Office LTSC 2024 for 64-bit editions
• Microsoft Office LTSC 2024 for 32-bit editions
• Microsoft Office LTSC 2021 for 32-bit editions
• Microsoft Office LTSC 2021 for 64-bit editions
• Microsoft Office LTSC for Mac 2021
• Microsoft 365 Apps for Enterprise for 64-bit Systems
• Microsoft 365 Apps for Enterprise for 32-bit Systems
• Microsoft Office 2019 for 64-bit editions
• Microsoft Office 2019 for 32-bit editions

CVE-2026-40369 – Windows Kernel Elevation of Privilege Vulnerability

Severity: Important

Subscriptions Required

• Advanced Threat Protection
• Advanced Cloud Sandbox

Affected Software

• Windows 11 Version 24H2 for ARM64-based Systems
• Windows 11 Version 26H1 for ARM64-based Systems
• Windows 11 version 26H1 for x64-based Systems
• Windows Server 2025
• Windows 11 Version 24H2 for x64-based Systems
• Windows 11 Version 25H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows Server 2025 (Server Core installation)

CVE-2026-40397 – Windows Common Log File System Driver Elevation of Privilege Vulnerability

Severity: Important

Subscriptions Required

• Advanced Threat Protection
• Advanced Cloud Sandbox

Affected Software

• Windows Server 2012 R2
• Windows Server 2012 R2 (Server Core installation)
• Windows Server 2012
• Windows Server 2012 (Server Core installation)
• Windows Server 2016 (Server Core installation)
• Windows Server 2016
• Windows 10 Version 1607 for x64-based Systems
• Windows 10 Version 1607 for 32-bit Systems
• Windows 11 Version 26H1 for ARM64-based Systems
• Windows 11 version 26H1 for x64-based Systems
• Windows Server 2025
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows 11 Version 24H2 for x64-based Systems
• Windows 11 Version 23H2 for x64-based Systems
• Windows 11 Version 23H2 for ARM64-based Systems
• Windows Server 2022, 23H2 Edition (Server Core installation)
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 25H2 for ARM64-based Systems
• Windows Server 2025 (Server Core installation)
• Windows 10 Version 22H2 for 32-bit Systems
• Windows 10 Version 22H2 for ARM64-based Systems
• Windows 10 Version 22H2 for x64-based Systems
• Windows 10 Version 21H2 for 32-bit Systems
• Windows 10 Version 21H2 for ARM64-based Systems
• Windows 10 Version 21H2 for x64-based Systems
• Windows Server 2019 (Server Core installation)
• Windows Server 2019
• Windows Server 2022 (Server Core installation)
• Windows 10 Version 1809 for 32-bit Systems
• Windows Server 2022
• Windows 10 Version 1809 for x64-based Systems

CVE-2026-40398 – Windows Remote Desktop Services Elevation of Privilege Vulnerability

Severity: Important

Subscriptions Required

• Advanced Threat Protection
• Advanced Cloud Sandbox

Affected Software

• Windows Server 2012 R2 (Server Core installation)
• Windows Server 2012 R2
• Windows Server 2012 (Server Core installation)
• Windows Server 2012
• Windows Server 2016 (Server Core installation)
• Windows Server 2016
• Windows 10 Version 1607 for x64-based Systems
• Windows 10 Version 1607 for 32-bit Systems
• Windows 11 Version 26H1 for ARM64-based Systems
• Windows 11 version 26H1 for x64-based Systems
• Windows Server 2025
• Windows 11 Version 24H2 for x64-based Systems
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows Server 2022, 23H2 Edition (Server Core installation)
• Windows 11 Version 23H2 for x64-based Systems
• Windows 11 Version 23H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 25H2 for ARM64-based Systems
• Windows Server 2025 (Server Core installation)
• Windows 10 Version 22H2 for 32-bit Systems
• Windows 10 Version 22H2 for ARM64-based Systems
• Windows 10 Version 22H2 for x64-based Systems
• Windows 10 Version 21H2 for x64-based Systems
• Windows 10 Version 21H2 for ARM64-based Systems
• Windows 10 Version 21H2 for 32-bit Systems
• Windows Server 2022 (Server Core installation)
• Windows Server 2022
• Windows Server 2019 (Server Core installation)
• Windows Server 2019
• Windows 10 Version 1809 for x64-based Systems
• Windows 10 Version 1809 for 32-bit Systems

CVE-2026-41103 – Microsoft SSO Plugin for Jira & Confluence Elevation of Privilege Vulnerability

Severity: Critical

Subscriptions Required

• Advanced Threat Protection
• Advanced Cloud Sandbox

Affected Software

• Microsoft Confluence SAML SSO plugin
• Microsoft JIRA SAML SSO plugin