Patch tracker / KB5094123

KB5094123: Windows Server 2019 Security Update (June 2026)

KB5094123 is a Critical security update for Windows Server 2019, released 2026-06-09. It closes 89 CVEs with a maximum CVSS of 9.8. The most likely of them to be attacked is CVE-2026-41108, which FIRST.org rates at 54% probability of exploitation in the next 30 days.

Update summary

Critical
2026-06-09
Released
89
CVEs fixed
9.8
Max CVSS
Critical
Severity
Deploy this cycle
Fixes 89 CVEs for Windows Server 2019. No confirmed in-the-wild exploitation in this set today.

Fixes 89 CVEs. Most severe CVSS 9.8 (Critical). EPSS exploit probability up to 54%. 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: 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.

Senserva found thisread these before you deploy broadly

Microsoft documents 3 known issues with this update.

  • Microsoft Office applications might fail to open from certain third-party apps
  • Deleting from Recycle Bin displays an internal file name
  • OneDrive shortcut in File Explorer might not work in administrator mode

The full text, quoted from Microsoft

Microsoft Update Catalog: download KB5094123Microsoft support article
Senserva AI Opinion for KB5094123

KB5094123 is a large June 2026 rollup for Windows 10 1809 and Windows Server 2019 that fixes 89 CVEs, topping out at Critical severity with a CVSS of 9.8. The highest EPSS here is 54 percent, which is unusually elevated for an update with no CISA KEV or ransomware links yet, suggesting at least one flaw is a realistic near-term exploitation target. Server 2019 fleets and legacy 1809 endpoints carry the exposure.

Do this: Deploy KB5094123 to all Windows Server 2019 and Windows 10 1809 systems this cycle, prioritizing internet-facing 2019 servers given the CVSS 9.8 Critical entry.

AI-generated from public data, 2026-07-26. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for KB5094123

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

Full tracking and change history for KB5094123

Released
2026-06-09
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 KB5094123 is installed

Elevated PowerShell. No output means it is not installed.

Known issues, from Microsoft

Quoted from Microsoft's support article for KB5094123 (checked 2026-08-04). Verify against the article before acting.

Microsoft Office applications might fail to open from certain third-party apps

Symptoms

Microsoft has received reports of an issue in which certain third-party applications might be unable to launch Microsoft Office applications or open documents after installing the Windows updates released on or after June 9, 2026. This issue affects certain third-party applications that use OLE automation to interact with Microsoft Office applications. In some cases, the Office application or document might fail to open without displaying an error message.

Affected Microsoft Office applications might include Word, Excel, PowerPoint, Access, and other Microsoft Office applications when launched from within the affected third-party application.

Reports indicate that this issue may affect applications such as CCH Engagement, Workpaper Manager, dental software (such as Dentrix and Softdent), and Zotero; other similar applications might also be impacted.

Third-party information disclaimer

The third-party products listed are manufactured by companies that are independent of Microsoft. We make no warranty, implied or otherwise, about the performance or reliability of these products.

Resolution

This issue is resolved in Windows updates released on and after July 14, 2026 such as KB5099538 . We recommend you install the latest Windows update for your device as it contains important improvements and ...

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.

CVESeverityCVSSEPSSExploited
CVE-2026-33828Critical9.854%No
CVE-2026-34335Critical9.854%No
CVE-2026-40404Critical9.854%No
CVE-2026-40409Critical9.854%No
CVE-2026-41092Critical9.854%No
CVE-2026-41108Critical9.854%No
CVE-2026-42828Critical9.854%No
CVE-2026-42836Critical9.854%No
CVE-2026-42837Critical9.854%No
CVE-2026-42903Critical9.854%No
CVE-2026-42905Critical9.854%No
CVE-2026-42907Critical9.854%No
CVE-2026-42908Critical9.854%No
CVE-2026-42909Critical9.854%No
CVE-2026-42911Critical9.854%No
CVE-2026-42912Critical9.854%No
CVE-2026-42914Critical9.854%No
CVE-2026-42916Critical9.854%No
CVE-2026-42968Critical9.854%No
CVE-2026-42969Critical9.854%No
CVE-2026-42970Critical9.854%No
CVE-2026-42971Critical9.854%No
CVE-2026-42972Critical9.854%No
CVE-2026-42973Critical9.854%No
CVE-2026-42977Critical9.854%No
CVE-2026-42978Critical9.854%No
CVE-2026-42979Critical9.854%No
CVE-2026-42980Critical9.854%No
CVE-2026-42983Critical9.854%No
CVE-2026-42984Critical9.854%No
CVE-2026-42985Critical9.854%No
CVE-2026-42986Critical9.854%No
CVE-2026-42987Critical9.854%No
CVE-2026-42989Critical9.854%No
CVE-2026-42991Critical9.854%No
CVE-2026-42992Critical9.854%No
CVE-2026-44799Critical9.854%No
CVE-2026-44801Critical9.854%No
CVE-2026-44802Critical9.854%No
CVE-2026-44803Critical9.854%No
CVE-2026-44805Critical9.854%No
CVE-2026-44812Critical9.854%No
CVE-2026-44815Critical9.854%No
CVE-2026-45586Critical9.854%No
CVE-2026-45588Critical9.854%No
CVE-2026-45592Critical9.854%No
CVE-2026-45593Critical9.854%No
CVE-2026-45594Critical9.854%No
CVE-2026-45595Critical9.854%No
CVE-2026-45596Critical9.854%No
CVE-2026-45598Critical9.854%No
CVE-2026-45599Critical9.854%No
CVE-2026-45601Critical9.854%No
CVE-2026-45602Critical9.854%No
CVE-2026-45603Critical9.854%No
CVE-2026-45605Critical9.854%No
CVE-2026-45606Critical9.854%No
CVE-2026-45607Critical9.854%No
CVE-2026-45608Critical9.854%No
CVE-2026-45634Critical9.854%No
CVE-2026-45635Critical9.854%No
CVE-2026-45636Critical9.854%No
CVE-2026-45637Critical9.854%No
CVE-2026-45638Critical9.854%No
CVE-2026-45639Critical9.854%No
CVE-2026-45642Critical9.854%No
CVE-2026-45653Critical9.854%No
CVE-2026-45655Critical9.854%No
CVE-2026-45656Critical9.854%No
CVE-2026-45658Critical9.854%No
CVE-2026-47288Critical9.854%No
CVE-2026-47289Critical9.854%No
CVE-2026-47291Critical9.854%No
CVE-2026-47648Critical9.854%No
CVE-2026-47653Critical9.854%No
CVE-2026-47654Critical9.854%No
CVE-2026-47656Critical9.854%No
CVE-2026-48563Critical9.854%No
CVE-2026-48568Critical9.854%No
CVE-2026-48570Critical9.854%No
CVE-2026-48573Critical9.854%No
CVE-2026-48574Critical9.854%No
CVE-2026-48575Critical9.854%No
CVE-2026-48576Critical9.854%No
CVE-2026-48578Critical9.854%No
CVE-2026-48583Critical9.854%No
CVE-2026-49160Critical9.854%No
CVE-2026-50507Critical9.854%No
CVE-2026-8863Critical9.854%No

Scope and sources

Affected products
Also released in June 2026

KB5094139

8 CVEs · High · exploited

KB5094140

8 CVEs · High · exploited

KB5094142

8 CVEs · High · exploited

KB5094144

8 CVEs · High · exploited

KB5087423

66 CVEs · Critical

KB5087539

66 CVEs · Critical

KB5089466

61 CVEs · Critical

KB5089549

61 CVEs · Critical

The full month, summarized: Microsoft Patch Tuesday.

Authoritative references
Official KB5094123 page (Microsoft Support)Microsoft Update CatalogMicrosoft Security Update Guide

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

New to a term on this page? CVE, KB, KEV, CVSS, and EPSS are each explained once, on the Senserva security lexicon. Reference: Microsoft CVE and vulnerability management and the Microsoft patching guide.
Provided as is, without warranty; verify against the vendor advisory before acting. Data notice and terms.