Patch tracker / KB5099536
KB5099536: Windows Server 2019 Security Update (July 2026)
KB5099536 is a Critical security update for Windows Server 2019, released 2026-07-14. It closes 389 CVEs with a maximum CVSS of 9.9. At least one of them is actively exploited (CISA KEV), so this is a deploy-first update. The most likely of them to be attacked is CVE-2026-42982, which FIRST.org rates at 64% probability of exploitation in the next 30 days.
Update summary
Fixes 389 CVEs. At least one is actively exploited (CISA KEV). Most severe CVSS 9.9 (Critical). EPSS exploit probability up to 64%. Among the top 25% 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: KB5094041 (2026-08-11). 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.
- Windows Server Update Services (WSUS) does not display error details
KB5099536 is an unusually large rollup for Windows 10 1809 and Windows Server 2019, fixing 388 CVEs including one rated Critical at CVSS 9.9 and at least one that is already on the CISA KEV list (though not tied to ransomware). Any organization still running the 1809 branch or Server 2019 is exposed, and the KEV listing means at least one flaw here is confirmed exploited in the wild.
Do this: Prioritize deploying KB5099536 to your Windows Server 2019 and Windows 10 1809 fleet now, starting with internet-facing and domain-critical systems given the confirmed KEV exploitation.
AI-generated from public data, 2026-07-25. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5099536
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5099536
- Released
- 2026-07-14
- Last changed
- 2026-07-29
- Changes tracked
- 3
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.
Microsoft revised KB5099536 on 2026-07-29: CVEs fixed 388 to 389.
- 2026-07-29 CVEs fixed 388 to 389
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 KB5099536 is installed
Elevated PowerShell. No output means it is not installed.
Known issues, from Microsoft
Quoted from Microsoft's support article for KB5099536 (checked 2026-08-11). Verify against the article before acting.
Windows Server Update Services (WSUS) does not display error details
After installing KB5070881 or later updates, Windows Server Update Services (WSUS) does not display synchronization error details within its error reporting. This functionality is temporarily removed to address the Remote Code Execution Vulnerability, CVE-2025-59287 .
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 July 2026
KB5099444
185 CVEs · Critical · exploitedKB5099445
174 CVEs · Critical · exploitedKB5099535
261 CVEs · Critical · exploitedKB5099538
312 CVEs · Critical · exploitedKB5099539
314 CVEs · Critical · exploitedKB5099540
326 CVEs · Critical · exploitedKB5101649
383 CVEs · Critical · exploitedKB5101650
380 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.