Patch tracker / KB5082123
KB5082123: Windows Server 2019 Security Update (April 2026)
KB5082123 is a Critical security update for Windows Server 2019, released 2026-04-14. It closes 106 CVEs with a maximum CVSS of 9.8. At least one of them is actively exploited (CISA KEV), so it is urgent, and Microsoft lists 1 known issue: test it before broad deployment. It is the seventh largest of the 60 updates Microsoft shipped that month, by CVEs closed.
Before you deploy: Microsoft lists 1 known issue for this update.
Our data comes from Microsoft, CISA and other public sources, and it can be wrong or out of date. If you are unsure, check the linked source before you act, and tell us when we are wrong so we can fix it.
Update summary
Fixes 106 CVEs. At least one is actively exploited (CISA KEV). Most severe CVSS 9.8 (Critical). EPSS exploit probability up to 3.5%. 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: KB5126651 (2026-10-13). 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 documents 1 known issue with this update.
- Domain controllers might restart repeatedly after installing this update
KB5082123 is a large April 2026 rollup for Windows 10 1809 and Windows Server 2019 that closes 108 CVEs, topped by a Critical flaw rated CVSS 9.8 with a 64% EPSS score, meaning exploitation is already probable rather than theoretical. At least one of these CVEs is on the CISA KEV list, confirming active exploitation in the wild, though none are currently tied to ransomware campaigns. Anyone still running the 1809 branch or Server 2019 domain infrastructure is directly exposed, and the KEV entry means attackers already know a working path in.
Do this: Deploy KB5082123 to your Server 2019 and Windows 10 1809 hosts now, prioritizing internet-facing and domain-role machines given the 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 KB5082123
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5082123
- Released
- 2026-04-14
- Last changed
- 2026-10-15
- Changes tracked
- 7
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.
- 2026-08-19 CVEs fixed 108 to 107
Recorded by Senserva on the dates shown, from the MSRC release feed. This is what moved and when, which neither the vendor advisory nor NVD publishes.
Check if KB5082123 is installed
Elevated PowerShell. No output means it is not installed.
Known issues, from Microsoft
Quoted from Microsoft's support article for KB5082123 (checked 2026-09-10). Microsoft lists 1 known issue. Verify against the article before acting.
Domain controllers might restart repeatedly after installing this update
Symptoms
After installing this update, domain controllers in environments with multiple domains in the forest that use Privileged Access Management (PAM), might experience LSASS crashes during startup. As a result, affected domain controllers might restart repeatedly, preventing authentication and directory services from functioning, and potentially rendering the domain unavailable.
Resolution
This issue is addressed in out-of-band update KB5091573 .
Remote Desktop security warnings might not display correctly
Symptoms
After installing this update, the security warning that appears when opening Remote Desktop (RDP) files might not display correctly in some cases.
This issue might occur when you use more than one monitor with different display scaling settings (for example, one display set to 100% and another set to 125%). When this happens, the warning window might show overlapping text or partially hidden buttons, which can make the message difficult to read or interact with.
Resolution
This issue is resolved in Windows updates released on and after May 12, 2026 (such as KB5087538 ). We recommend you install the latest Windows update for your device as it contains important improvements and issue resolutions, including this one.
Applies to: Windows 10 Enterprise LTSC 2019
This security update includes ...
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 April 2026
KB5082052
114 CVEs · Critical · exploitedKB5082060
120 CVEs · Critical · exploitedKB5082063
123 CVEs · Critical · exploitedKB5082142
115 CVEs · Critical · exploitedKB5082198
86 CVEs · Critical · exploitedKB5082200
106 CVEs · Critical · exploitedKB5083768
119 CVEs · Critical · exploitedKB5083769
120 CVEs · Critical · exploitedThe full month, summarized: Microsoft Patch Tuesday.
- Authoritative references
See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.