Patch tracker / KB5078734
KB5078734: Windows Server 2019 Security Update (March 2026)
KB5078734 is a High security update for Windows Server 2019, released 2026-03-10. It closes 40 CVEs with a maximum CVSS of 8.8. It is the fourth largest of the 38 updates Microsoft shipped that month, by CVEs closed.
Update summary
Fixes 40 CVEs. Most severe CVSS 8.8 (High). EPSS exploit probability up to 4.7%. Among the top half of tracked Microsoft updates by EPSS exploit probability.
A newer security update for Windows 10 Version 1809 for 32-bit Systems has shipped since this one: KB5089548 (2026-07-14). 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.
KB5078734 is a March 2026 rollup for Windows 10 1809 and Windows Server 2019 that closes 40 CVEs, with the worst rated High at CVSS 8.8. None are on the CISA KEV list or tied to ransomware, and the highest EPSS is only 4 percent, so exploitation is not observed yet. The exposure is broad here because 1809 and Server 2019 remain common in legacy line of business and domain controller roles that lag on patching.
Do this: Schedule KB5078734 in your next patch window for all Windows 10 1809 and Server 2019 hosts, prioritizing domain controllers and internet-facing servers.
AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5078734
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5078734
- Released
- 2026-03-10
- Last changed
- 2026-07-24
- 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 KB5078734 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 March 2026
KB5002843
3 CVEs · HighKB5002845
4 CVEs · HighKB5002850
4 CVEs · HighKB5077464
2 CVEs · HighKB5077465
2 CVEs · HighKB5077466
3 CVEs · HighKB5077468
3 CVEs · HighKB5077469
2 CVEs · HighThe full month, summarized: Microsoft Patch Tuesday.
- Authoritative references
See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.