Patch tracker / KB5071543
KB5071543: Windows Server 2016 Security Update (December 2025)
KB5071543 is a High security update for Windows Server 2016, released 2025-12-09. It closes 15 CVEs with a maximum CVSS of 8.8. It is the ninth largest of the 36 updates Microsoft shipped that month, by CVEs closed.
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Update summary
Fixes 15 CVEs. Most severe CVSS 8.8 (High). EPSS exploit probability up to 2.5%. Among the top half of tracked Microsoft updates by EPSS exploit probability.
A newer security update for Windows 10 Version 1607 for 32-bit Systems has shipped since this one: KB5126649 (2026-10-13). 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.
KB5071543 is the December 9, 2025 rollup for Windows 10 version 1809 and Windows Server 2019, closing 15 CVEs with a highest rating of High (CVSS 8.8). None are on the CISA KEV list or tied to ransomware, and the highest EPSS is only 2 percent, so exploitation pressure is currently low despite the elevated CVSS. Anyone still running the 1809 branch or Server 2019 domain infrastructure is exposed.
Do this: Schedule KB5071543 through your normal patch ring for all Server 2019 and Windows 10 1809 hosts this cycle rather than treating it as an emergency out-of-band push.
AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5071543
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5071543
- Released
- 2025-12-09
- Last changed
- 2026-07-08
- 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 KB5071543 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.
| CVE | Severity | CVSS | EPSS | Exploited |
|---|---|---|---|---|
| CVE-2025-62549 | High | 8.8 | 4.6% | No |
| CVE-2025-54100 | High | 7.8 | 4.6% | No |
| CVE-2025-59517 | High | 7.8 | 4.6% | No |
| CVE-2025-62455 | High | 7.8 | 2.5% | No |
| CVE-2025-62458 | High | 7.8 | 2.5% | No |
| CVE-2025-62466 | High | 7.8 | 4.6% | No |
| CVE-2025-62470 | High | 7.8 | 4.6% | No |
| CVE-2025-62472 | High | 7.8 | 4.6% | No |
| CVE-2025-62474 | High | 7.8 | 4.6% | No |
| CVE-2025-62571 | High | 7.8 | 4.6% | No |
| CVE-2025-64661 | High | 7.8 | 4.6% | No |
| CVE-2025-62565 | High | 7.3 | 4.6% | No |
| CVE-2025-62573 | High | 7.0 | 4.6% | No |
| CVE-2025-62473 | Medium | 6.5 | 4.6% | No |
| CVE-2025-62567 | Medium | 5.3 | 4.6% | No |
Scope and sources
- Affected products
- Also released in December 2025
KB5071413
28 CVEs · High · exploitedKB5071417
30 CVEs · High · exploitedKB5071542
30 CVEs · High · exploitedKB5071544
26 CVEs · High · exploitedKB5071546
28 CVEs · High · exploitedKB5071547
29 CVEs · High · exploitedKB5072014
33 CVEs · High · exploitedKB5072033
34 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.