The November 2021 Patch Tuesday update addresses 55 vulnerabilities, including two critical zero-day vulnerabilities in Microsoft Exchange and Excel that need immediate attention. In addition to normal updates for Windows OS, Office, and development tools, the release emphasizes risk management around the 287 vulnerabilities outlined in DHS CISA's directive. Affected products include various versions of Windows, with several critical updates requiring restarts and some known issues identified with different system performances.