Patch tracker / KB5082126
KB5082126: Windows Server 2012 R2 Security Update (April 2026)
KB5082126 is a High security update for Windows Server 2012 R2, released 2026-04-14. It closes 60 CVEs with a maximum CVSS of 8.8. Microsoft documents 1 known issue for this update, quoted below.
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Our data comes from Microsoft, CISA and other public sources, and it can be wrong or out of date.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 60 CVEs. Most severe CVSS 8.8 (High). 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 Server 2012 R2 has shipped since this one: KB5126836 (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.
- We are currently not aware of any issues with this update. For the most up-to-date information about known issues for Windows Server 2012 R2, please...
KB5082126 is a large April 2026 rollup fixing 62 CVEs across Windows 11 26H1 (ARM64 and x64) and Windows 10 1809, with a top rating of High (CVSS 8.8). One of its CVEs is on the CISA KEV list, meaning it is confirmed exploited in the wild, and the highest EPSS of 64% signals a real near-term exploitation likelihood even though none of the flaws are tied to known ransomware campaigns.
Do this: Deploy KB5082126 to your 26H1 and 1809 systems now, prioritizing internet-facing and privileged hosts 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 KB5082126
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5082126
- Released
- 2026-04-14
- Last changed
- 2026-10-15
- Changes tracked
- 5
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 KB5082126 is installed
Elevated PowerShell. No output means it is not installed.
Known issues, from Microsoft
Quoted from Microsoft's support article for KB5082126 (checked 2026-07-22). Microsoft lists 1 known issue. Verify against the article before acting.
We are currently not aware of any issues with this update. For the most up-to-date information about known issues for Windows Server 2012 R2, please go to the Windows release health dashboard .
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 · exploitedKB5082123
106 CVEs · Critical · exploitedKB5082142
115 CVEs · Critical · exploitedKB5082198
86 CVEs · Critical · exploitedKB5082200
106 CVEs · Critical · exploitedKB5083768
119 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.