CVE-2026-66804: Microsoft Windows Cross Device Service Elevation of Privilege Vulnerability

Published Aug 11, 2026
·
Updated

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

Other sources

Microsoft Windows Cross Device Service Elevation of Privilege Vulnerability

— Microsoft

Affected Software

10 affected componentsFixes available
Microsoft Windows Cross Device Service
Microsoft Windows 11=24H2
10.0.26100.916810.0.26000.9106
Microsoft Windows 11=26H1
10.0.28000.2704
Microsoft Windows 11=24H2
10.0.26100.916810.0.26100.9106
Microsoft Windows 11=26H1
10.0.28000.2704
Microsoft Windows 11=25H2
10.0.26200.916810.0.26100.9106
Microsoft Windows 10=22H2
10.0.19045.7663
Microsoft Windows 10=22H2
10.0.19045.7663
Microsoft Windows 11=25H2
10.0.26200.916810.0.26100.9106
Microsoft Windows 10=22H2
10.0.19045.7663

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.28000.2704Patch KB5121000
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26100.9168Fixed in 10.0.26000.9106Patch KB5120994
  3. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26200.9168Fixed in 10.0.26100.9106Patch KB5120994
  4. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26100.9168Fixed in 10.0.26100.9106Patch KB5120994
  5. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.19045.7663Patch KB5120249

Event History

Aug 11, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
Description
CVE Published
via MITRE·05:05 PM
Data Sourced
via MITRE·05:05 PM
DescriptionSeverity
Data Sourced
via NVD·05:19 PM
DescriptionSeverityWeakness
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Frequently Asked Questions

1

What is the severity of CVE-2026-66804?

CVE-2026-66804 has a high severity rating of 7.8.

2

How do I fix CVE-2026-66804?

To fix CVE-2026-66804, ensure that your Microsoft Windows operating system is updated with the latest security patches from Microsoft.

3

What systems are affected by CVE-2026-66804?

CVE-2026-66804 affects Microsoft Windows 10, Microsoft Windows 11, and Microsoft Windows Cross Device Service.

4

What type of vulnerability is CVE-2026-66804?

CVE-2026-66804 is a Cross Device Service Elevation of Privilege vulnerability due to improper access control.

5

Who can exploit CVE-2026-66804?

An authorized attacker can exploit CVE-2026-66804 to elevate privileges locally on the affected systems.

Company

Resources

Contact

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