KB5101649: Windows Server 2019 Security Update (July 2026)

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Download KB5101649

Get the official update for KB5101649. The download and file size for each supported product are on the Microsoft Update Catalog page.

Update summary

Senserva AI Opinion for KB5101649

KB5101649 is a Security Update for Windows 11 Version 26H1 on ARM64 and x64 systems, and it addresses CVE-2026-50661, a publicly disclosed BitLocker zero-day. Because this flaw touches BitLocker, machines relying on disk encryption for physical security are the exposed population, and public disclosure means attack details are already circulating. Note the data is provisional since Microsoft has not yet published per-update CVE detail for this July 2026 cycle.

Do this: Deploy KB5101649 to all Windows 11 26H1 ARM64 and x64 devices now, prioritizing any that depend on BitLocker for at-rest data protection.

AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for KB5101649

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

Full tracking and change history for KB5101649

Senserva began recording day-to-day change history on 2026-07-07, and refreshes it several times a day. Release dates are historical where Microsoft publishes them; revision history is tracked from that date forward, so it does not include changes made before then.

Exploitation and severity

Fixes 382 CVEs. Most severe CVSS 9.9 (Critical). EPSS exploit probability up to 3.2%.

Among the top half of tracked Microsoft updates by EPSS exploit probability.

What to do

Elevated priority: high severity or a meaningful exploitation probability, sooner if an affected product is internet-facing. Senserva flags whether KB5101649 is missing on your devices.

Check if KB5101649 is installed

Copy-paste PowerShell: one machine, or your whole fleet in one pass. No output means the update is not installed.

Get-HotFix covers Windows updates. Office, SharePoint, and Exchange server updates show under installed updates in Programs and Features, or check the Update Catalog history.

Known issues, from Microsoft

Quoted from Microsoft's support article for KB5101649 (checked 2026-07-21). Verify against the article before acting.

Microsoft is not currently aware of any issues with this update.

Writing about KB5101649? Cite this page

Copy-paste for a blog post, forum answer, or internal doc. The link always carries the current risk data.

CVEs fixed by this update

Sorted exploited-first, then by CVSS. Every CVE links to its Senserva page with the full risk facts, references, and a ready-to-paste AI prompt.

What the press says about this update

Trusted-source coverage of the CVEs this update fixes, pulled live from their own feeds.

Affected products

• Windows 10 Version 1809 for 32-bit Systems
• Windows 10 Version 1809 for x64-based Systems
• Windows Server 2019

Also released in July 2026

The highest-risk updates from the same release:

The full month, summarized: Microsoft Patch Tuesday.

How to install KB5101649

Any of these paths delivers KB5101649; most organizations already have one of the first three running:

• Intune update rings (Windows Update for Business): the update flows on each ring's deferral schedule.
• Windows Autopatch: rings, rollout, and pause or rollback are managed for you; exploited updates can be expedited.
• WSUS / Configuration Manager: approve KB5101649 for your device groups and set a deadline.
• Manual: download from the Update Catalog above and install; fine for a handful of machines, unmanageable at any real scale.

After the rollout, verify rather than assume: update compliance reporting in Intune or Autopatch shows which devices actually installed it, and Siemserva reads Intune, Defender, Autopatch, and Azure Update Manager together to show the devices still missing KB5101649, ranked by exploitation.

Common questions about KB5101649

Does KB5101649 have known issues?

Yes. Microsoft's support article documents known issues for KB5101649 (checked 2026-07-21). The Known issues section on this page quotes it; verify against the article before acting.

Is KB5101649 urgent?

KB5101649 is rated Critical with a maximum CVSS of 9.9. No active exploitation is confirmed yet, so schedule it in your prompt patch cycle.

How do I download KB5101649?

From the Microsoft Update Catalog (linked on this page), or let Intune, Windows Update for Business, Windows Autopatch, or WSUS deliver it. The catalog page lists the download for each supported product.

How do I deploy KB5101649 with Intune?

Assign a Windows Update ring (quality update policy) to the device groups and the update flows on the ring's deferral schedule. For urgent updates, Intune expedite policies can bypass the ring deferrals. Verify the rollout with update compliance reporting rather than assuming delivery.

Can I ask my own AI about KB5101649?

Yes. This page includes a free, ready-to-paste AI prompt containing KB5101649's key facts: severity, CVE count, exploitation status, and the download link. Copy it into Claude, ChatGPT, or Copilot for a rollout plan; the data is refreshed three times a day (5 AM, 12:30 PM, and 7 PM US Central).

Authoritative references