Patch tracker / CVE reference / CVE-2025-21204
CVE-2025-21204
CVE-2025-21204 is a high severity Microsoft vulnerability with a CVSS score of 7.8. Its EPSS score puts the probability of exploitation in the next 30 days at 14%. Microsoft has shipped the fix: deploy one of the 14 updates below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.
Risk summary
Not in the CISA KEV catalog. EPSS exploit probability 14%. CVSS 7.8 (High).
This CVE is among the lower half of tracked Microsoft CVEs by EPSS exploit probability.
CVE-2025-21204 is a Windows Process Activation elevation of privilege flaw with a High severity rating (CVSS 8.8) that lets a local attacker gain higher privileges. Exposure is broad across both new and legacy builds, spanning Windows Server 2025 including Server Core through Windows 10 Version 1809 32-bit systems. The 13% EPSS score is elevated for a privilege escalation issue, meaning it is a plausible second stage after any initial foothold, even though it is not yet in CISA KEV or tied to ransomware.
Do this: Deploy Microsoft's patch for CVE-2025-21204 across your Windows Server 2025 and Windows 10 1809 fleet, prioritizing multi-user and internet-facing hosts where a low-privilege foothold is most likely.
AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2025-21204
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Official patch(es) for CVE-2025-21204
Elevated priority: high severity or a meaningful exploitation probability, sooner if an affected product is internet-facing. In Intune or Defender, confirm whether the fixing updates KB5055518, KB5055519, KB5055521, KB5055523, KB5055526, KB5055527, KB5055528, KB5055547, KB5055557, KB5055561, KB5055570, KB5055581, KB5055596, KB5055609 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-2025-21204. 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.
Scope and sources
- Affected products
- Fixed by the same updates
- Authoritative references
Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.