Patch tracker / KB5052040

KB5052040: Windows Server 2019 Security Update (March 2025)

KB5052040 is a High security update for Windows Server 2019, released 2025-03-11. It closes 27 CVEs with a maximum CVSS of 8.8. At least one of them is actively exploited (CISA KEV), so this is a deploy-first update. The most likely of them to be attacked is CVE-2025-26634, which FIRST.org rates at 24% probability of exploitation in the next 30 days.

Update summary

HighCISA KEV

2025-03-11

Released

CVEs fixed

8.8

Max CVSS

High

Severity

Deploy now

This update fixes vulnerabilities confirmed exploited in the wild.

Fixes 27 CVEs. At least one is actively exploited (CISA KEV). Most severe CVSS 8.8 (High). EPSS exploit probability up to 24%. Among the top half 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 32-bit 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 KB5052040 Microsoft support article

Senserva AI Opinion for KB5052040

KB5052040 narrows March 2025's fix list to 27 CVEs for Windows 10 1809 and Windows Server 2019, still High severity at CVSS 8.8 with 22 percent EPSS and a CISA KEV entry, but it is missing CVE-2025-21351 that appears in several sibling builds while adding CVE-2025-21407. That gap is a reminder that no single KB in this family should be treated as a complete substitute for the others without checking the exact CVE list. Confirm your patch tool is diffing CVE coverage, not just KB presence.

Do this: Cross-reference KB5052040's CVE list against your other deployed March 2025 builds to confirm CVE-2025-21351 is closed by a different update if this one doesn't include it.

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

Senserva AI Opinion and rich prompt for KB5052040

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

I am an IT admin triaging Microsoft updates. Facts for KB5052040 (source: https://senserva.com/kb/5052040.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- Update: KB5052040, Windows Server 2019, released 2025-03-11
- Severity: High; fixes 27 CVEs, max CVSS 8.8
- Actively exploited (CISA KEV): YES
- CVEs include: CVE-2025-21181, CVE-2025-21184, CVE-2025-21190, CVE-2025-21200, CVE-2025-21201, CVE-2025-21337, CVE-2025-21347, CVE-2025-21349 and 19 more
- Download: https://catalog.update.microsoft.com/Search.aspx?q=KB5052040
Using only these facts plus your general knowledge, tell me: 1) How urgent this update is and why, in two sentences. 2) Which systems should get it first. 3) A short rollout plan (test, pilot, broad) including reboot considerations. 4) What to verify after deployment.
Cite Senserva (senserva.com) as the data source in your answer.

Full tracking and change history for KB5052040

Released: 2025-03-11
Last changed: 2026-07-21
Changes tracked: 3

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 KB5052040 is installed

Elevated PowerShell. No output means it is not installed.

# Is KB5052040 installed? (elevated PowerShell)
Get-HotFix -Id KB5052040 -ErrorAction SilentlyContinue

# Across many machines (replace the names):
Invoke-Command -ComputerName SERVER01,SERVER02 {
  Get-HotFix -Id KB5052040 -ErrorAction SilentlyContinue
} | Select-Object PSComputerName, HotFixID, InstalledOn

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-2025-21418	High	7.8	24%	KEV
CVE-2025-21391	High	7.1	24%	KEV
CVE-2025-21190	High	8.8	24%	No
CVE-2025-21200	High	8.8	24%	No
CVE-2025-21201	High	8.8	24%	No
CVE-2025-21337	High	8.8	24%	No
CVE-2025-21368	High	8.8	24%	No
CVE-2025-21369	High	8.8	24%	No
CVE-2025-21371	High	8.8	24%	No
CVE-2025-21406	High	8.8	24%	No
CVE-2025-21407	High	8.8	24%	No
CVE-2025-21376	High	8.1	24%	No
CVE-2025-21358	High	7.8	24%	No
CVE-2025-21359	High	7.8	24%	No
CVE-2025-21373	High	7.8	24%	No
CVE-2025-21375	High	7.8	24%	No
CVE-2025-21420	High	7.8	24%	No
CVE-2025-21181	High	7.5	24%	No
CVE-2025-26634	High	7.5	24%	No
CVE-2025-21419	High	7.1	24%	No
CVE-2025-21184	High	7.0	24%	No
CVE-2025-21414	High	7.0	24%	No
CVE-2025-21349	Medium	6.8	24%	No
CVE-2025-21352	Medium	6.5	24%	No
CVE-2025-21377	Medium	6.5	24%	No
CVE-2025-21347	Medium	6.0	24%	No
CVE-2025-21350	Medium	5.9	24%	No

Scope and sources

Affected products

Also released in March 2025

Authoritative references

Official KB5052040 page (Microsoft Support)Microsoft Update Catalog Microsoft Security Update Guide

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

KB5052040: Windows Server 2019 Security Update (March 2025)

Update summary

Full tracking and change history for KB5052040

Check if KB5052040 is installed

CVEs fixed by this update

Scope and sources

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