Patch tracker / KB5063871
KB5063871: Windows Server 2019 Security Update (August 2025)
KB5063871 is a Critical security update for Windows Server 2019, released 2025-08-12. It closes 48 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
Fixes 48 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.
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.
KB5063871 is the August 12, 2025 rollup for Windows 10 1809 and Windows Server 2019, closing 48 CVEs including one rated Critical at CVSS 9.8. The highest EPSS across the batch is 38 percent, which is elevated for a patch with no CISA KEV or ransomware links yet, meaning exploit development is plausible before it becomes public. Server 2019 fleets, including Server Core installations, carry the most exposure given their network reachability.
Do this: Deploy KB5063871 to your Server 2019 hosts first, prioritizing internet-facing and domain-critical systems, then roll out to Windows 10 1809 endpoints.
AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5063871
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5063871
- 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 KB5063871 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.
Scope and sources
- Affected products
- Also released in August 2025
KB5058379
36 CVEs · High · exploitedKB5058383
39 CVEs · High · exploitedKB5058384
44 CVEs · High · exploitedKB5058385
42 CVEs · High · exploitedKB5058387
33 CVEs · High · exploitedKB5058392
42 CVEs · High · exploitedKB5058405
38 CVEs · High · exploitedKB5058411
44 CVEs · High · exploitedThe full month, summarized: Microsoft Patch Tuesday.
- Authoritative references
See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.