202310 Cumulative Update For Windows 11 For X64based Systems Kb5031358 Exclusive May 2026

Executive summary

KB5031358 is the October 10, 2023 cumulative monthly security update (LCU) for Windows 11 (notably for version 21H2 builds like 22000.2538) for x64 (AMD64) systems. It is a combined package that includes a servicing stack update (SSU) and the latest cumulative fixes and security patches. The release focuses on security hardening, reliability improvements to the servicing stack, and a small set of functional adjustments (including HTTP/2 registry tuning). Some editions of 21H2 reached end of servicing on that date; the update was distributed via Windows Update, WSUS and the Microsoft Update Catalog (standalone ~350.5 MB for x64).

  1. Backup BitLocker recovery keys to Active Directory or print them.
  2. Test on a non‑critical machine if you use self‑encrypting SSDs.
  3. Check for driver updates – especially NVMe storage and network drivers.
  4. Uninstall any preview updates (KB5030310 – optional) to avoid component overlap.

Remediation / Troubleshooting steps (if issues occur)

  1. Boot into Safe Mode and uninstall the update if system unstable.
  2. Roll back using System Restore (if a restore point exists).
  3. Use DISM and SFC:

    Security Patches: Fixed critical vulnerabilities such as the HTTP/2 Rapid Reset Attack (CVE-2023-44487) and an information disclosure flaw in Microsoft WordPad (CVE-2023-36563). Executive summary KB5031358 is the October 10, 2023

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