Windows 11 patch KB5083769 breaks backups #cybersecurity #windows11 #patchtuesday

Microsoft's April 14, 2026 Windows 11 cumulative update (KB5083769) patches 167 vulnerabilities — including two actively-exploited zero-days. It also breaks third-party backup software via a Volume Shadow Copy Service (VSS) regression. The update affects Windows 11 24H2 (build 26100.8246) and 25H2 (build 26200.8246). Microsoft's confirmed known-issue list includes Acronis Cyber Protect Cloud, Macrium Reflect, NinjaOne Backup, and UrBackup Server. Users have also reported similar VSS failures with Veeam, though Veeam isn't on Microsoft's confirmed list. The two actively-exploited zero-days patched are CVE-2026-32202 (zero-click Windows Shell flaw) and CVE-2026-32201 (Microsoft SharePoint Server spoofing). Microsoft has acknowledged the bug and is working on an out-of-band fix; the next regular Patch Tuesday is May 12, 2026. AskWoody (Susan Bradley's long-running Windows-patch tracker) issued an MS-DEFCON 3 alert telling admins to hold off on deploying KB5083769 in production until Microsoft ships a fix. Sources: https://www.bleepingcomputer.com/news/microsoft/april-kb5083769-windows-11-update-causes-backup-software-failures/ https://support.microsoft.com/en-us/topic/april-14-2026-kb5083769-os-builds-26200-8246-and-26100-8246-22f90ae5-9f26-40ac-9134-6a586a71163b https://www.askwoody.com/2026/ms-defcon-3-kb5083769-causes-backup-issues/ More on cybersecurity, privacy, scams, and homelab on Hake Hardware. New shorts every weekday.