Microsoft releases Windows 11 updates and emergency .NET security fixes

Microsoft has rolled out several significant updates for its Windows ecosystem. The Windows 11 26H2 update, also known as the 2026 Update, is now generally available for compatible devices running versions 24H2 and 25H2. This release focuses on system reliability, security, and usability, including refinements to the Start menu and File Explorer. Notably, the KB5127936 cumulative update introduces new customization options for the right-click context menu, allowing users to organize commands and manage application extensions.

In response to critical vulnerabilities, Microsoft issued emergency out-of-band security updates for .NET 8, .NET 9, .NET 10, and .NET 11 Release Candidate 3. These fixes address a buffer overflow flaw in the Brotli compression technology (CVE-2026-111497) that could allow unauthenticated attackers to read or corrupt memory, and a Linux-specific privilege escalation vulnerability (CVE-2026-114148).

Additionally, an emergency cumulative update (KB5134133) has been released specifically for Windows 11 versions 24H2 through 26H2 to secure air-gapped or disconnected enterprise environments against certificate compromises. Meanwhile, Windows Server 2022 administrators are advised that November and December 2026 security updates will require system restarts, temporarily suspending standard hotpatching capabilities.