Patch tracker / CVE reference / CVE-2026-50300
CVE-2026-50300
CVE-2026-50300 is a critical severity Microsoft vulnerability with a CVSS score of 9.9. Its EPSS score puts the probability of exploitation in the next 30 days at 64%. Microsoft has shipped the fix: deploy one of the 7 updates below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.
Risk summary
Senserva AI Opinion for CVE-2026-50300
CVE-2026-50300 is an information disclosure flaw in the Windows DWM Core Library, the desktop compositor component, rated Medium severity with a CVSS score of 5.5. Only the 1809 branch is named here: Windows 10 Version 1809 in both 32-bit and x64 forms plus Windows Server 2019. Because DWM leaks tend to expose memory contents that reveal addresses or data useful for chaining, this is more valuable to an attacker as a stepping stone than as a standalone exploit.
Do this: Apply the current Windows security update to your Windows 10 1809 and Windows Server 2019 systems, prioritizing any remaining 1809 endpoints still in service.
AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2026-50300
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2026-50300
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
Exploitation and severity
Not in the CISA KEV catalog. EPSS exploit probability 64%. CVSS 9.9 (Critical).
This CVE is among the top half of tracked Microsoft CVEs by EPSS exploit probability.
Official patch(es) for CVE-2026-50300
High priority: EPSS puts the odds of near-term exploitation high. In Intune or Defender, confirm whether the fixing updates KB5099535, KB5099536, KB5099538, KB5099539, KB5099540, KB5101649, KB5101650 are installed across the affected products. Senserva does this automatically across your tenant and flags every missing patch.
Apply the Microsoft security updates below to fix CVE-2026-50300. Each KB page carries the Microsoft Update Catalog download, Microsoft's known issues for the update, a copy-paste PowerShell check for whether it is installed, and the Senserva AI read.
Affected products
Fixed by the same updates
If you are patching CVE-2026-50300, the same updates also fix these:
Authoritative references
Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.