Microsoft · ServicingStack update · May 12, 2026

KB5087423: May 2026 cumulative update for Windows Server 2025

KB5087423, released May 12, 2026, fixes 66 CVEs across 2 products. None of them is reported as exploited. Patch Radar priority: Urgent.

Urgent
CVEs closed
66
5 rated Critical
Exploited
0
None reported
Exploitation more likely
9
Vendor assessment
Highest EPSS
0.7962
99th percentile

Priority of the 66 CVEs

Patch now 0 Urgent 14 High 41 Routine 11

Applies to

ProductBuild after install
Windows Server 202526100.32772
Windows Server 2025 (Server Core installation)26100.32772

CVEs this fix closes

PriorityCVEComponentImpactCVSSEPSSExploitation
Urgent CVE-2026-41089 Windows Netlogon Remote Code Execution 9.8 0.7962 Exploitation Less Likely
Urgent CVE-2026-40369 Windows Kernel Elevation of Privilege 7.8 0.0473 More likely
Urgent CVE-2026-41096 Microsoft Windows DNS Remote Code Execution 9.8 0.0270 Exploitation Unlikely
Urgent CVE-2026-40398 Windows Remote Desktop Elevation of Privilege 7.8 0.0267 More likely
Urgent CVE-2026-33835 Windows Cloud Files Mini Filter Driver Elevation of Privilege 7.8 0.0212 More likely
Urgent CVE-2026-33840 Windows Win32K - ICOMP Elevation of Privilege 7.8 0.0201 More likely
Urgent CVE-2026-33837 Windows TCP/IP Elevation of Privilege 7.8 0.0184 More likely
Urgent CVE-2026-35416 Windows Ancillary Function Driver for WinSock Elevation of Privilege 7.0 0.0165 More likely
Urgent CVE-2026-35421 Windows GDI Remote Code Execution 7.8 0.0053 Exploitation Unlikely
Urgent CVE-2026-40403 Windows Win32K - GRFX Remote Code Execution 8.8 0.0043 Exploitation Less Likely
Urgent CVE-2026-35417 Windows Win32K - ICOMP Elevation of Privilege 7.8 0.0035 More likely
Urgent CVE-2026-33841 Windows Kernel Elevation of Privilege 7.8 0.0031 More likely
Urgent CVE-2026-32161 Windows Native WiFi Miniport Driver Remote Code Execution 7.5 0.0030 Exploitation Less Likely
Urgent CVE-2026-40397 Windows Common Log File System Driver Elevation of Privilege 7.8 0.0027 More likely
High CVE-2026-35424 Windows Internet Key Exchange (IKE) Protocol Denial of Service 7.5 0.0119 Exploitation Unlikely
High CVE-2026-40405 Windows TCP/IP Denial of Service 7.5 0.0108 Exploitation Less Likely
High CVE-2026-40406 Windows TCP/IP Information Disclosure 7.5 0.0093 Exploitation Less Likely
High CVE-2026-40415 Windows TCP/IP Remote Code Execution 8.1 0.0079 Exploitation Unlikely
High CVE-2026-40414 Windows TCP/IP Denial of Service 7.4 0.0053 Exploitation Unlikely
High CVE-2026-34332 Windows Kernel-Mode Drivers Remote Code Execution 8.0 0.0051 Exploitation Unlikely
High CVE-2026-34329 Windows Message Queuing Remote Code Execution 8.8 0.0046 Exploitation Less Likely
High CVE-2026-40413 Windows TCP/IP Denial of Service 7.4 0.0040 Exploitation Less Likely
High CVE-2026-33838 Windows Message Queuing Elevation of Privilege 7.8 0.0040 Exploitation Less Likely
High CVE-2026-35415 Windows Storage Spaces Controller Elevation of Privilege 7.8 0.0033 Exploitation Less Likely
High CVE-2026-41095 Data Deduplication Elevation of Privilege 7.8 0.0033 Exploitation Less Likely
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