Microsoft's October 2025 Patch Tuesday addressed 175 vulnerabilities, including two zero-day elevation-of-privilege flaws: CVE-2025-24990, related to the legacy ltmdm64.sys Agere Modem driver, and CVE-2025-59230, affecting the Remote Access Connection Manager. Five vulnerabilities were classified as critical, including CVE-2025-59246 (remote code execution in Azure Entra ID), CVE-2025-55315 (ASP.NET Core vulnerability), CVE-2025-49708 (Microsoft Graphics Component bug), CVE-2025-59287 (Windows Server Update Service flaw), and CVE-2025-59228 (SharePoint vulnerability). The update (KB5066835) also resolved usability issues, such as print preview hangs and input detection failures. Microsoft notified administrators about the expiration of Secure Boot certificates in June 2026. Windows 11 users can install the update via Settings > Windows Update, requiring a system restart and data backup before installation.