Patch tracker / KB5126649

KB5126649: Windows Server 2016 Security Update (October 2026)

KB5126649 is a High security update for Windows Server 2016, released 2026-10-13. It closes 2 CVEs with a maximum CVSS of 7.8. It is the 69th largest of the 75 updates Microsoft shipped that month, by CVEs closed.

Update summary

High

2026-10-13

Released

CVEs fixed

7.8

Max CVSS v3

High

Severity

Deploy this cycle

Fixes 2 CVEs for Windows Server 2016. No confirmed in-the-wild exploitation in this set today.

Fixes 2 CVEs. Most severe CVSS 7.8 (High).

Microsoft Update Catalog: download KB5126649 Microsoft support article

Senserva AI Opinion and rich prompt for KB5126649

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 KB5126649 (source: https://senserva.com/kb/5126649.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed daily (early morning US Central)):
- Update: KB5126649, Windows Server 2016, released 2026-10-13
- Severity: High; fixes 2 CVEs, max CVSS 7.8
- Actively exploited (CISA KEV): no
- CVEs include: CVE-2026-69950, CVE-2026-83863
- Download: https://catalog.update.microsoft.com/Search.aspx?q=KB5126649
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 KB5126649

Released: 2026-10-13
Last changed: 2026-10-13
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 KB5126649 is installed

Elevated PowerShell. No output means it is not installed.

# Is KB5126649 installed? (elevated PowerShell)
Get-HotFix -Id KB5126649 -ErrorAction SilentlyContinue

# Across many machines (replace the names):
Invoke-Command -ComputerName SERVER01,SERVER02 {
  Get-HotFix -Id KB5126649 -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-2026-69950	High	7.8	-	No
CVE-2026-83863	High	7.8	-	No

Scope and sources

Affected products

Also released in October 2026

Authoritative references

Official KB5126649 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.

KB5126649: Windows Server 2016 Security Update (October 2026)

Update summary

Full tracking and change history for KB5126649

Check if KB5126649 is installed

CVEs fixed by this update

Scope and sources

KB5099444

KB5099445

KB5099535

KB5099536

KB5099538

KB5099539

KB5099540

KB5101649