Microsoft · Security update · May 12, 2026

KB5087538: May 2026 cumulative update for Windows 10 1809

KB5087538, released May 12, 2026, fixes 55 CVEs across 4 products. None of them is reported as exploited. Patch Radar priority: Urgent.

Urgent
CVEs closed
55
4 rated Critical
Exploited
0
None reported
Exploitation more likely
6
Vendor assessment
Highest EPSS
0.7962
99th percentile

Priority of the 55 CVEs

Patch now 0 Urgent 10 High 37 Routine 8

Applies to

ProductBuild after install
Windows 10 Version 1809 for 32-bit Systems17763.8755
Windows 10 Version 1809 for x64-based Systems17763.8755
Windows Server 201917763.8755
Windows Server 2019 (Server Core installation)17763.8755

CVEs this fix closes

PriorityCVEComponentImpactCVSSEPSSExploitation
Urgent CVE-2026-41089 Windows Netlogon Remote Code Execution 9.8 0.7962 Exploitation Less Likely
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-2026-33837 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-2026-32161 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-2026-40406 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-2026-34329 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
High CVE-2026-40401 Windows TCP/IP Denial of Service 7.1 0.0033 Exploitation Unlikely
High CVE-2026-40399 Windows TCP/IP Elevation of Privilege 7.8 0.0033 Exploitation Less Likely
High CVE-2026-34343 Windows Application Identity (AppID) Subsystem Elevation of Privilege 7.8 0.0033 Exploitation Less Likely
High CVE-2026-35420 Windows Kernel Elevation of Privilege 7.8 0.0032 Exploitation Less Likely
High CVE-2026-34344 Windows Ancillary Function Driver for WinSock Elevation of Privilege 7.8 0.0031 Exploitation Less Likely
High CVE-2026-34330 Windows Win32K - GRFX Elevation of Privilege 7.8 0.0030 Exploitation Unlikely
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