Patch tracker / KB5075943

KB5075943: Windows Server 2019 Security Update (February 2026)

KB5075943 is a High security update for Windows Server 2019, released 2026-02-10. 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-2026-21519, which FIRST.org rates at 26% probability of exploitation in the next 30 days.

Update summary

HighCISA KEV

2026-02-10

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 26%. 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 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 KB5075943 Microsoft support article

Senserva AI Opinion for KB5075943

KB5075943 is the February 10, 2026 rollup for Windows 10 1809 and Windows Server 2019, fixing 27 CVEs topping out at High severity (CVSS 8.8). One of these CVEs is already listed in the CISA Known Exploited Vulnerabilities catalog, meaning active exploitation is confirmed in the wild even though none are tied to ransomware campaigns yet. With a highest EPSS of 26%, the exploitation odds warrant treating this as more urgent than a routine monthly batch.

Do this: Deploy KB5075943 to all Windows 10 1809 and Server 2019 hosts now, prioritizing internet-facing servers because of the confirmed KEV-listed CVE.

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

Senserva AI Opinion and rich prompt for KB5075943

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 KB5075943 (source: https://senserva.com/kb/5075943.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- Update: KB5075943, Windows Server 2019, released 2026-02-10
- Severity: High; fixes 27 CVEs, max CVSS 8.8
- Actively exploited (CISA KEV): YES
- CVEs include: CVE-2026-20846, CVE-2026-21222, CVE-2026-21231, CVE-2026-21234, CVE-2026-21235, CVE-2026-21236, CVE-2026-21237, CVE-2026-21238 and 19 more
- Download: https://catalog.update.microsoft.com/Search.aspx?q=KB5075943
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 KB5075943

Released: 2026-02-10
Last changed: 2026-02-10
Changes tracked: 1

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 KB5075943 is installed

Elevated PowerShell. No output means it is not installed.

# Is KB5075943 installed? (elevated PowerShell)
Get-HotFix -Id KB5075943 -ErrorAction SilentlyContinue

# Across many machines (replace the names):
Invoke-Command -ComputerName SERVER01,SERVER02 {
  Get-HotFix -Id KB5075943 -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-2026-21510	High	8.8	26%	KEV
CVE-2026-21513	High	8.8	26%	KEV
CVE-2026-21519	High	7.8	26%	KEV
CVE-2026-21533	High	7.8	26%	KEV
CVE-2026-21525	Medium	6.2	26%	KEV
CVE-2026-21249	High	8.8	26%	No
CVE-2026-21255	High	8.8	26%	No
CVE-2026-21231	High	7.8	26%	No
CVE-2026-21236	High	7.8	26%	No
CVE-2026-21238	High	7.8	26%	No
CVE-2026-21239	High	7.8	26%	No
CVE-2026-21240	High	7.8	26%	No
CVE-2026-21246	High	7.8	26%	No
CVE-2026-21251	High	7.8	26%	No
CVE-2026-20846	High	7.5	26%	No
CVE-2026-21243	High	7.5	26%	No
CVE-2026-21235	High	7.3	26%	No
CVE-2026-21244	High	7.3	26%	No
CVE-2026-21247	High	7.3	26%	No
CVE-2026-21248	High	7.3	26%	No
CVE-2026-21234	High	7.0	26%	No
CVE-2026-21237	High	7.0	26%	No
CVE-2026-21241	High	7.0	26%	No
CVE-2026-21242	High	7.0	26%	No
CVE-2026-21253	High	7.0	26%	No
CVE-2026-21508	High	7.0	26%	No
CVE-2026-21222	Medium	5.5	26%	No

Scope and sources

Affected products

Also released in February 2026

Authoritative references

Official KB5075943 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.

KB5075943: Windows Server 2019 Security Update (February 2026)

Update summary

Full tracking and change history for KB5075943

Check if KB5075943 is installed

CVEs fixed by this update

Scope and sources

KB5075897

KB5075899

KB5075904

KB5075906

KB5075912

KB5075941

KB5075942

KB5075970