CVE intelligence

CVE-2026-66804

Vulnerability intelligence

Published Aug 11, 2026Sources checked Oct 28, 2026

7.8HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-66804 and is rated High severity with a CVSS score of 7.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 7, 2026

Vendor remediation details

Install KB5120249. Install KB5121003. Install KB5120994. Install KB5121000.

Vendor-listed releases

10.0.19045.7663
10.0.26200.9168
10.0.26200.9106
10.0.26100.9168
10.0.26100.9106
10.0.28000.2704

CISA KEVNot listedBased on the latest collected catalog

EPSS0.3%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-66804?

Improper access control in Windows Cross Device Service allows an authorized attacker to elevate privileges locally.

Source: NVD