ReviewHigh

CVE-2026-66804

Microsoft Windows 10 Version 22H2, Windows 11 Version 24H2, Windows 11 Version 25H2

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

PRIORITY ASSESSMENT

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability-

Technical severityCVSS 7.8

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

Product: Microsoft Windows 10 Version 22H2, Windows 11 Version 24H2, Windows 11 Version 25H2
Affected versions: >= 10.0.19045.0 < 10.0.19045.7663, >= 10.0.26100.0 < 10.0.26100.9168, >= 10.0.26200.0 < 10.0.26200.9168, >= 10.0.28000.0 < 10.0.28000.2704, < 10.0.26100.9106, < 10.0.26200.9106
Fixed versions: 10.0.19045.7663, 10.0.26100.9106, 10.0.26200.9106, 10.0.28000.2704

Confirm exposure before applying a vendor-supported change.

1
Identify
Confirm that Microsoft Windows 10 Version 22H2, Windows 11 Version 24H2, Windows 11 Version 25H2 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.