Patch tracker / KB5063899

KB5063899: Windows Server 2019 Security Update (August 2025)

KB5063899 is a Critical security update for Windows Server 2019, released 2025-08-12. It closes 57 CVEs with a maximum CVSS of 9.8. The most likely of them to be attacked is CVE-2025-49751, which FIRST.org rates at 38% probability of exploitation in the next 30 days.

Update summary

Critical
2025-08-12
Released
57
CVEs fixed
9.8
Max CVSS
Critical
Severity
Deploy this cycle
Fixes 57 CVEs for Windows Server 2019. No confirmed in-the-wild exploitation in this set today.

Fixes 57 CVEs. Most severe CVSS 9.8 (Critical). EPSS exploit probability up to 38%. Among the top 25% of tracked Microsoft updates by EPSS exploit probability.

Senserva found thiswe track every release for this product line, so we can tell you this package is behind

A newer security update for Windows 10 Version 1809 for x64-based Systems has shipped since this one: KB5094041 (2026-08-11). For cumulative update families the newer package includes these fixes, so installing that one is usually the shorter path. Verify against your own update rings before you skip this package.

Microsoft Update Catalog: download KB5063899Microsoft support article
Senserva AI Opinion for KB5063899

KB5063899 is the August 12, 2025 rollup for Windows 10 1809 and Windows Server 2019, closing 57 CVEs including one rated Critical at CVSS 9.8. The peak EPSS of 38 percent is unusually high for a patch with nothing yet in the CISA KEV catalog, meaning exploitation is more probable than typical here even without confirmed in-the-wild abuse.

Do this: Deploy KB5063899 to your Server 2019 and Windows 10 1809 fleet this cycle, prioritizing internet-facing servers given the CVSS 9.8 rating and 38 percent EPSS.

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

Senserva AI Opinion and rich prompt for KB5063899

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

Full tracking and change history for KB5063899

Released
2025-08-12
Last changed
2026-07-13
Changes tracked
2

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.

Check if KB5063899 is installed

Elevated PowerShell. No output means it is not installed.

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.

CVESeverityCVSSEPSSExploited
CVE-2025-53766Critical9.838%No
CVE-2025-50171Critical9.138%No
CVE-2025-50163High8.838%No
CVE-2025-53131High8.838%No
CVE-2025-53143High8.838%No
CVE-2025-53144High8.838%No
CVE-2025-53145High8.838%No
CVE-2025-53778High8.838%No
CVE-2025-50177High8.138%No
CVE-2025-50160High8.038%No
CVE-2025-50162High8.038%No
CVE-2025-50164High8.038%No
CVE-2025-53720High8.038%No
CVE-2025-49761High7.838%No
CVE-2025-50155High7.838%No
CVE-2025-50168High7.838%No
CVE-2025-50170High7.838%No
CVE-2025-50173High7.838%No
CVE-2025-50176High7.838%No
CVE-2025-53132High7.838%No
CVE-2025-53141High7.838%No
CVE-2025-53149High7.838%No
CVE-2025-53151High7.838%No
CVE-2025-53154High7.838%No
CVE-2025-53155High7.838%No
CVE-2025-53723High7.838%No
CVE-2025-53724High7.838%No
CVE-2025-53725High7.838%No
CVE-2025-53726High7.838%No
CVE-2025-53722High7.538%No
CVE-2025-50159High7.338%No
CVE-2025-50161High7.338%No
CVE-2025-49762High7.038%No
CVE-2025-50158High7.038%No
CVE-2025-50167High7.038%No
CVE-2025-53134High7.038%No
CVE-2025-53135High7.038%No
CVE-2025-53137High7.038%No
CVE-2025-53140High7.038%No
CVE-2025-53142High7.038%No
CVE-2025-53147High7.038%No
CVE-2025-53718High7.038%No
CVE-2025-53721High7.038%No
CVE-2025-49751Medium6.838%No
CVE-2025-49743Medium6.738%No
CVE-2025-50154Medium6.538%No
CVE-2025-50166Medium6.538%No
CVE-2025-50172Medium6.538%No
CVE-2025-53716Medium6.538%No
CVE-2025-50156Medium5.738%No
CVE-2025-50157Medium5.738%No
CVE-2025-53138Medium5.738%No
CVE-2025-53148Medium5.738%No
CVE-2025-53153Medium5.738%No
CVE-2025-53719Medium5.738%No
CVE-2025-53136Medium5.538%No
CVE-2025-53156Medium5.538%No

Scope and sources

Affected products
Also released in August 2025

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36 CVEs · High · exploited

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39 CVEs · High · exploited

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44 CVEs · High · exploited

KB5058385

42 CVEs · High · exploited

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33 CVEs · High · exploited

KB5058392

42 CVEs · High · exploited

KB5058405

38 CVEs · High · exploited

KB5058411

44 CVEs · High · exploited

The full month, summarized: Microsoft Patch Tuesday.

Authoritative references
Official KB5063899 page (Microsoft Support)Microsoft Update CatalogMicrosoft Security Update Guide

See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.

New to a term on this page? CVE, KB, KEV, CVSS, and EPSS are each explained once, on the Senserva security lexicon. Reference: Microsoft CVE and vulnerability management and the Microsoft patching guide.
Provided as is, without warranty; verify against the vendor advisory before acting. Data notice and terms.