KB5099535: Windows Server 2019 Security Update (July 2026)

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Download KB5099535

Get the official update for KB5099535. The download and file size for each supported product are on the Microsoft Update Catalog page.

Update summary

Senserva AI Opinion for KB5099535

KB5099535 is the July 2026 Security Update for .NET Framework 3.5 and 4.7.2 on Windows 10 Version 1607 and Windows Server 2016, including Server Core. The July cycle it belongs to carries two zero-days, CVE-2026-56155 in AD FS which is exploited in the wild and CVE-2026-50661 in BitLocker which is publicly disclosed, so servers running AD FS on 2016 warrant priority attention. Note the data is provisional because Microsoft has not yet published the per-update CVE detail, so the exact CVEs bundled into this specific .NET package are not confirmed.

Do this: Deploy KB5099535 across your Windows 10 1607 and Server 2016 fleet this cycle, prioritizing any Server 2016 hosts running AD FS given the actively exploited CVE-2026-56155.

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

Senserva AI Opinion and rich prompt for KB5099535

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

Full tracking and change history for KB5099535

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 260 CVEs. At least one is actively exploited (CISA KEV). Most severe CVSS 9.9 (Critical). EPSS exploit probability up to 7.5%.

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

What to do

Treat as urgent: it is being exploited in the wild (CISA KEV), so patch ahead of items that are not. Senserva flags whether KB5099535 is missing on your devices.

Check if KB5099535 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 KB5099535 (checked 2026-07-21). Verify against the article before acting.

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

Applies to: Windows 10 Enterprise LTSB 2016 and Windows 10 IoT Enterprise 2016 LTSB

This security update includes fixes and improvements that are a part of the following update:

June 9, 2026—KB5094122 (OS Build 14393.9230)

The following is a summary of the issues that this update addresses. The bold text within the brackets indicates the item or area of the change we are documenting.

[OLE Automation (known issue)] Fixed: Addresses a compatibility issue in OLE Automation (oleaut32.dll) that was introduced by the June 2026 security update. Some applications that use the IDispatch::Invoke method to call COM methods with BYREF parameters that share the same underlying storage might fail. These failures can include parameter marshaling errors or automation call failures. This update corrects how parameter ownership is managed and restores expected application behavior.

[File Explorer (known issue)] Fixed: An issue where the OneDrive shortcut in File Explorer stops working when File Explorer is run with administrative mode.

[Recycle Bin (known issue)] Fixed: This update addresses an issue where the confirmation dialog might display an internal Recycle Bin file name instead of the original file name when permanently deleting a file.

[Secure Boot] This update includes additional high confidence device targeting data, ...

Writing about KB5099535? 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 KB5099535

Any of these paths delivers KB5099535; 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. For this update, consider an expedite policy: it bypasses deferrals for exactly this fix-now case.
• Windows Autopatch: rings, rollout, and pause or rollback are managed for you; exploited updates can be expedited.
• WSUS / Configuration Manager: approve KB5099535 for your device groups and set a deadline (deadline, not just approval, for an exploited fix).
• 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 KB5099535, ranked by exploitation.

Common questions about KB5099535

Does KB5099535 have known issues?

Yes. Microsoft's support article documents known issues for KB5099535 (checked 2026-07-21). The Known issues section on this page quotes it; verify against the article before acting.

Is KB5099535 urgent?

Yes. KB5099535 fixes at least one vulnerability in the CISA Known Exploited Vulnerabilities catalog, meaning attackers are using it in the wild. Deploy it first.

How do I download KB5099535?

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 KB5099535 with Intune?

Assign a Windows Update ring (quality update policy) to the device groups and the update flows on the ring's deferral schedule. Because KB5099535 fixes an actively exploited CVE, an Intune expedite policy is the right tool: it bypasses configured deferrals and pushes the update as soon as devices check in. Verify the rollout with update compliance reporting rather than assuming delivery.

Can I ask my own AI about KB5099535?

Yes. This page includes a free, ready-to-paste AI prompt containing KB5099535'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