Patch tracker / KB5087470
KB5087470: Windows Server 2019 Security Update (May 2026)
KB5087470 is a Critical security update for Windows Server 2019, released 2026-05-12. It closes 39 CVEs with a maximum CVSS of 9.8. The most likely of them to be attacked is CVE-2026-33834, which FIRST.org rates at 80% probability of exploitation in the next 30 days.
Update summary
Fixes 39 CVEs. Most severe CVSS 9.8 (Critical). EPSS exploit probability up to 80%. Among the top 10% 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: 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.
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, please go...
KB5087470 is the May 2026 rollup for Windows 10 Version 1809 and Windows Server 2019, closing 39 CVEs including one rated Critical at CVSS 9.8 with an 80 percent EPSS score, which signals a high statistical likelihood of exploitation soon. No CVE here is in the CISA KEV catalog or tied to ransomware yet, but the combination of a 9.8 severity flaw and 80 percent EPSS on Server 2019 makes this a priority. Domain controllers and other Server 2019 workloads running the 1809 branch are the most exposed.
Do this: Deploy KB5087470 to your Windows Server 2019 and 1809 fleet in this patch cycle, prioritizing internet-facing and domain controller systems.
AI-generated from public data, 2026-07-26. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5087470
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5087470
- Released
- 2026-05-12
- 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 KB5087470 is installed
Elevated PowerShell. No output means it is not installed.
Known issues, from Microsoft
Quoted from Microsoft's support article for KB5087470 (checked 2026-08-06). 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, 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.
| CVE | Severity | CVSS | EPSS | Exploited |
|---|---|---|---|---|
| CVE-2026-21530 | Critical | 9.8 | 80% | No |
| CVE-2026-32161 | Critical | 9.8 | 80% | No |
| CVE-2026-32170 | Critical | 9.8 | 80% | No |
| CVE-2026-32209 | Critical | 9.8 | 80% | No |
| CVE-2026-33834 | Critical | 9.8 | 80% | No |
| CVE-2026-33837 | Critical | 9.8 | 80% | No |
| CVE-2026-33838 | Critical | 9.8 | 80% | No |
| CVE-2026-34329 | Critical | 9.8 | 80% | No |
| CVE-2026-34330 | Critical | 9.8 | 80% | No |
| CVE-2026-34331 | Critical | 9.8 | 80% | No |
| CVE-2026-34333 | Critical | 9.8 | 80% | No |
| CVE-2026-34334 | Critical | 9.8 | 80% | No |
| CVE-2026-34338 | Critical | 9.8 | 80% | No |
| CVE-2026-34341 | Critical | 9.8 | 80% | No |
| CVE-2026-34342 | Critical | 9.8 | 80% | No |
| CVE-2026-34343 | Critical | 9.8 | 80% | No |
| CVE-2026-34344 | Critical | 9.8 | 80% | No |
| CVE-2026-34347 | Critical | 9.8 | 80% | No |
| CVE-2026-34351 | Critical | 9.8 | 80% | No |
| CVE-2026-35416 | Critical | 9.8 | 80% | No |
| CVE-2026-35420 | Critical | 9.8 | 80% | No |
| CVE-2026-35421 | Critical | 9.8 | 80% | No |
| CVE-2026-35422 | Critical | 9.8 | 80% | No |
| CVE-2026-35423 | Critical | 9.8 | 80% | No |
| CVE-2026-35424 | Critical | 9.8 | 80% | No |
| CVE-2026-40377 | Critical | 9.8 | 80% | No |
| CVE-2026-40380 | Critical | 9.8 | 80% | No |
| CVE-2026-40382 | Critical | 9.8 | 80% | No |
| CVE-2026-40397 | Critical | 9.8 | 80% | No |
| CVE-2026-40398 | Critical | 9.8 | 80% | No |
| CVE-2026-40401 | Critical | 9.8 | 80% | No |
| CVE-2026-40403 | Critical | 9.8 | 80% | No |
| CVE-2026-40406 | Critical | 9.8 | 80% | No |
| CVE-2026-40407 | Critical | 9.8 | 80% | No |
| CVE-2026-40408 | Critical | 9.8 | 80% | No |
| CVE-2026-40413 | Critical | 9.8 | 80% | No |
| CVE-2026-40414 | Critical | 9.8 | 80% | No |
| CVE-2026-41089 | Critical | 9.8 | 80% | No |
| CVE-2026-42825 | Critical | 9.8 | 80% | No |
Scope and sources
- Affected products
- Also released in May 2026
KB5002863
9 CVEs · High · exploitedKB5002868
9 CVEs · High · exploitedKB5002870
9 CVEs · High · exploitedKB5078943
3 CVEs · CriticalKB5087420
56 CVEs · CriticalKB5087424
56 CVEs · CriticalKB5087471
42 CVEs · CriticalKB5087537
47 CVEs · CriticalThe full month, summarized: Microsoft Patch Tuesday.
- Authoritative references
See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.