KB5064010 Hotpatch for Windows 11 LTSC 2024 - Security, No-Restart Update (26100.4851)

August 12, 2025, saw Microsoft publish KB5064010 — a hotpatch for Windows 11 Enterprise LTSC 2024 that advances the OS to OS Build 26100.4851, delivering targeted security hardening without the broad-feature changes or mandatory restarts that administrators dread. This release is part of Microsoft’s expanding hotpatch program for Windows client devices and is presented as a combined package with the latest Servicing Stack Update (SSU), enabling safer, more reliable installation for managed enterprise fleets.

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Background​

Hotpatching has moved from a server‑first innovation into mainstream Windows client servicing during 2025. Microsoft’s intent is clear: reduce disruptive reboots while maintaining a rapid security posture for enterprise environments. The hotpatch model uses in‑memory code patching where possible and limits restart windows to the scheduled quarterly baselines. Microsoft’s documentation and IT Pro guidance describe a cadence of quarterly baseline updates (requiring restart) complemented by multiple hotpatch months (no restart required), giving administrators the ability to minimize downtime while staying current.
Windows 11 Enterprise LTSC 2024 (version 24H2) is treated specially: it’s a long‑term servicing channel that prioritizes stability, and Microsoft has extended the hotpatch capability to LTSC clients to allow mission‑critical endpoints (medical devices, industrial machines, ATMs, etc.) to receive security fixes with minimal service interruption. This makes KB5064010 significant for organizations that favor LTSC for its conservative feature set but must still respond to evolving threats.

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What KB5064010 Delivers​

Improvements and fixes (high level)​

• The update is described by Microsoft as delivering “miscellaneous security improvements to internal OS functionality.” No additional functional bugs or feature changes are enumerated in the public KB; Microsoft explicitly lists no other documented issues for this hotpatch. That wording indicates focused security hardening rather than service‑impacting feature work.
• KB5064010 is shipped with the latest SSU for the platform (the update bundle references SSU KB5065381, version 26100.4933), which is intended to reduce update failures and improve the reliability of future installs. Including the SSU with hotpatches reduces friction for administrators and lowers the chance of servicing stack related failures during rollout.
• For Arm64-managed environments, KB5064010 continues Microsoft’s public preview guidance by preserving the special prerequisites and enrollment mechanics required for hotpatch acceptance (details below). Microsoft reiterates that hotpatching on Arm64 devices remains in public preview and requires administrative preparation.

Files and build identifiers​

• Target OS Build after applying the hotpatch: 26100.4851.
• KB tracking number for the hotpatch: KB5064010.
• Associated Servicing Stack Update: KB5065381 (build 26100.4933).
• Distribution channels: Windows Update (automatic), Microsoft Update Catalog (manual), and WSUS for managed deployments.

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Why this matters to IT teams​

Hotpatches like KB5064010 tighten security while minimizing operational disruption — an attractive proposition for environments that require high availability. The advantages are straightforward:

• Reduced downtime: By design, hotpatch updates do not trigger device restart for the remainder of their servicing quarter, lowering the operational cost of frequent monthly patching.
• Faster protection: Hotpatches take effect immediately upon installation, providing rapid mitigation for discovered vulnerabilities without waiting for a scheduled restart window.
• Consistency with LTSC goals: LTSC customers retain a stable feature set while receiving security fixes — a crucial trade‑off for regulated and embedded systems.

However, this convenience comes with procedural obligations: hotpatching requires deliberate enrollment and configuration, and in some cases platform‑level readiness that administrators must validate before relying on it in production.

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Prerequisites and enrollment (detailed)​

KB5064010’s release notes reiterate Microsoft’s established hotpatch prerequisites. Administrators must confirm these before relying on hotpatch deliveries:

• Devices must run Windows 11 Enterprise, version 24H2, build 26100.4929 or later, and be on the current baseline update to be eligible for hotpatches.
• Devices should be managed through Microsoft Intune (Windows quality update policy that supports hotpatching) or Windows Autopatch for orchestration. Hotpatch enrollment is controlled by policy, and Intune’s quality update policy toggles hotpatch behavior. (learn.microsoft.com, support.microsoft.com)
• A qualifying license is required (for example, Windows 11 Enterprise E3/E5, Microsoft 365 F3, Windows 11 Education A3/A5, Microsoft 365 Business Premium, or Windows 365 Enterprise).
• Virtualization‑based security (VBS) must be enabled on managed endpoints.

Arm64-specific steps (public preview):

• Disable Compiled Hybrid PE (CHPE): Arm64 devices must have CHPE disabled to accept hotpatches. Microsoft gives two methods: a CSP-based DisableCHPE policy via Intune or setting a registry key:
• Registry: HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\HotPatchRestrictions = 1
• A restart is required once after setting this; afterwards devices remain eligible for hotpatches. (support.microsoft.com, techcommunity.microsoft.com)

Enrollment steps (high level):

• Create or edit a Windows quality update policy in Intune.
• Ensure “When available, apply without restarting the device” is set to Allow.
• Assign the policy to your Arm64 device group (or x64 groups for general availability scenarios).

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Deployment guidance and best practices​

Administrators should treat KB5064010 like any other security patch: validate, pilot, and stage rollout. Follow these practical steps:

• Inventory eligibility
• Verify device builds, licensing, VBS status, and CHPE settings for Arm64 devices.
• Identify devices that cannot accept hotpatches; those will receive the standard LCU (Latest Cumulative Update) which requires a restart.
• Pilot in small rings
• Test KB5064010 on a representative pilot group that mirrors production workloads (including enterprise applications, device drivers, peripheral integrations).
• Monitor for application compatibility regressions, driver resets, or unexpected telemetry anomalies.
• Monitor update health and telemetry
• Use Windows Update for Business/Intune reporting and endpoint management telemetry to watch update applicability, success rates, and post‑install error events. Bundled SSUs reduce installation faults, but they do not eliminate configuration- or firmware-level failures.
• Coordinate firmware and driver updates
• Some environments have firmware dependencies; ensure OEM firmware is current before applying hotpatch-only cycles. If firmware or driver updates are needed, those typically require restarts and should be scheduled during baselines.
• Maintain a rollback plan
• Hotpatches are designed to be minimally invasive, but unforeseen regressions can happen. Plan for incident response: document how to uninstall cumulative updates or apply recovery images where necessary, and be prepared to escalate to vendor support if a device becomes unstable.

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Security context: what Microsoft did — and what it didn’t disclose​

KB5064010’s public notes use the phrase “miscellaneous security improvements,” which is intentionally non‑specific. That phrasing is common for hotpatch releases that bundle multiple low‑profile security hardenings without tying them to discrete public CVE disclosures. Two important implications flow from this:

• Administrators should assume the patch includes fixes that could range from kernel hardening to mitigations for privilege escalation paths — but Microsoft has not enumerated CVEs or technical exploit details in the KB itself. For CVE-level mapping and exploitability guidance, consult Microsoft’s Security Update Guide and the monthly security rollup where applicable. If precise CVE mapping is required for compliance audits, those channels should be the first stop. (support.microsoft.com, bleepingcomputer.com)
• Lack of granular disclosure is not indicative of insignificance; rapid, low-noise fixes are often intended to minimize attacker awareness while delivering protection swiftly. Treat the update as operationally important and prioritize deployment to at‑risk endpoints.

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The Secure Boot certificate expiry — why KB5064010 reiterates urgency​

KB5064010’s page contains an explicit advisory: Secure Boot certificates used by most Windows devices will begin to expire in June 2026, and organizations must prepare for certificate rollover to avoid disruption to pre‑boot security updates and boot trust. Microsoft advises administrators to review and apply guidance to update KEK/DB certificates with the 2023 CA family before the 2011 certificates lapse.
This is a far‑reaching operational risk:

• If devices still present the 2011 CA versions when they expire, certain Secure Boot pre‑boot fixes may no longer install and, in extreme cases, platforms might fail to boot under current Secure Boot policies. OEM coordination plus staged rollout of updated certificates is required for many managed fleets. TechCommunity posts and Microsoft’s Secure Boot guidance explain the timeline and practical mitigations in depth. (techcommunity.microsoft.com, support.microsoft.com)
• Microsoft’s recommended path for most organizations is to allow Microsoft-managed Secure Boot certificate updates (via Windows Update) for devices that receive automatic updates. For air‑gapped, highly controlled, or firmware‑locked systems, administrators must follow the documented manual procedures or work with OEMs to push the updated certificates prior to June 2026. (support.microsoft.com, techcommunity.microsoft.com)

KB5064010 reiterates this broader advisory as a reminder: even hotpatch‑ready endpoints should be included in Secure Boot readiness assessments.

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Risks and potential pitfalls​

No Microsoft release is risk‑free, and KB5064010 is no exception. Consider these potential issues before broad deployment:

• Compatibility with enterprise security agents and low‑level drivers: Hotpatching modifies in‑memory code paths; poorly behaved third‑party kernel modules or endpoint detection and response (EDR) drivers may react unpredictably. Require vendor validation for any security or monitoring stack that relies on kernel hooks.
• Arm64 public preview caveats: If using Arm64 devices in production, remember hotpatching on Arm64 is still in public preview and requires CHPE to be disabled and additional registry/CSP steps. Production rollouts should be conservative until preview maturity improves. (support.microsoft.com, bleepingcomputer.com)
• Overreliance on “no restart” messaging: Hotpatch months reduce restarts but do not eliminate them forever. Feature updates, firmware, or some cumulative fixes still require restarts. Administrators must maintain restart windows and avoid indefinite deferral.
• Secure Boot certificate coordination risk: Organizations that overlook the certificate expiry program risk a loss of pre‑boot updateability and potential secure‑boot trust erosion in 2026. Don’t postpone certificate readiness work because it crosses multiple organizational boundaries (OS updates, firmware, and OEM coordination).

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Verification and cross‑checks​

Microsoft’s KB page for KB5064010 is authoritative for the release’s packaging, build number, and distribution channels; the company’s TechCommunity hotpatch blog and numerous independent outlets (including Windows IT Pro blog coverage and reputable security press) have documented both the operational mechanics of hotpatch and the enrollment prerequisites administrators must follow. Cross‑referencing these independent sources confirms the release model and practical instructions for Intune enrollment and CHPE disabling. (support.microsoft.com, techcommunity.microsoft.com, bleepingcomputer.com)
Where Microsoft’s KB is intentionally vague — specifically the phrase “miscellaneous security improvements” — administrators should consult the Security Update Guide for CVE listings and escalate to Microsoft support if compliance or audit reporting requires identifiable CVE mapping. If precise exploitability or CVE association is a gating factor for your change window, treat the release as higher priority but require vendor verification before mass rollout.

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Recommended rollout checklist (concise)​

• Verify each device’s eligibility (build, VBS status, license).
• For Arm64 devices, set CHPE disablement via CSP or registry and restart once.
• Create a Windows quality update policy in Intune and enable hotpatching for pilot groups. (support.microsoft.com, learn.microsoft.com)
• Pilot KB5064010 for 7–14 days; monitor application logs and endpoint telemetry.
• Stage wider rollout in phased rings, verifying critical application compatibility and driver behavior.
• Coordinate with OEMs on firmware updates and confirm Secure Boot certificate readiness for 2026.

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Final analysis — strengths and caution​

KB5064010 represents a steady, pragmatic evolution in Windows servicing for enterprise customers: it allows organizations to receive urgent security fixes with minimal operational friction and includes the SSU improvements necessary to help updates land cleanly. For LTSC customers, this is meaningful because it narrows the gap between stability and security without forcing feature churn.
Strengths:

• Operational efficiency: fewer forced restarts and faster protection against threats.
• Servicing reliability: bundled SSU reduces installation-related failure modes.
• Alignment with enterprise needs: supports LTSC stability while preserving security posture. (support.microsoft.com, techcommunity.microsoft.com)

Cautions:

• Opaque fix descriptions: Microsoft’s non‑specific wording requires admins to rely on telemetry and the Security Update Guide for deeper visibility. Treat undisclosed fixes as important but verify for compliance needs.
• Preview caveats for Arm64: additional configuration (CHPE disablement) and preview maturity require conservative deployment on Arm64 devices. (support.microsoft.com, bleepingcomputer.com)
• Secure Boot timetable: the certificate rollover program tied to mid‑2026 expirations is an operational imperative that crosses software and firmware domains; ignoring it risks broken pre‑boot security and updateability. (support.microsoft.com, techcommunity.microsoft.com)

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Conclusion​

KB5064010 (OS Build 26100.4851) is a targeted hotpatch that underscores Microsoft’s move to a less disruptive, more secure servicing model for Windows 11 Enterprise LTSC 2024. Administrators should treat this release as high‑priority for eligible devices: validate prerequisites, pilot the update, and use Intune or Windows Autopatch to manage staged rollouts. Simultaneously, IT teams must accelerate Secure Boot certificate readiness planning for the June 2026 timeline — a separate but related risk that KB5064010’s advisory rightly reminds organizations to address. The new hotpatch model balances uptime and security, but it shifts operational responsibility to administrators to ensure device eligibility, vendor compatibility, and firmware readiness before trusting no‑restart updates at scale. (support.microsoft.com, techcommunity.microsoft.com)

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Source: Microsoft Support August 12, 2025—KB5064010: Hotpatch for Windows 11 Enterprise LTSC 2024 (OS Build 26100.4851) - Microsoft Support