Microsoft Ships Windows 11 26H1 Cumulative Security Update KB5089548

Microsoft released KB5089548 for Windows 11 version 26H1, advancing systems to OS Build 28000.2113 and delivering the latest fixes from the May 2026 Security Updates guide. The cumulative update is available through standard support channels and the Microsoft Update Catalog, and Microsoft said it was not aware of any known issues affecting the release.

The package also carries forward non-security improvements from earlier preview and cumulative releases, including more reliable SSDP notifications and better compatibility for some games that use embedded web content by reducing the impact of JavaScript errors on in-game features. Microsoft also updated several AI components and bundled the servicing stack update KB5092761 (version 28000.2103) to improve update installation reliability.