CVE-2026-78444: Microsoft Failover Cluster Remote Code Execution Vulnerability

Published Sep 8, 2026
·
Updated

Microsoft Failover Cluster Remote Code Execution Vulnerability

Other sources

Untrusted pointer dereference in Windows Failover Cluster allows an unauthorized attacker to execute code over a network.

Microsoft

Affected Software

8 affected componentsFixes available
Microsoft Windows Server 2019<10.0.17763.9245
10.0.17763.9245
Microsoft Windows 10=1809
10.0.17763.9245
Microsoft Windows Server 2022<10.0.20348.5622
10.0.20348.5622
Microsoft Windows Server 2019<10.0.17763.9245
10.0.17763.9245
Microsoft Windows 10=1809
10.0.17763.9245
Microsoft Windows Server 2025<10.0.26100.33438
10.0.26100.33438
Microsoft Windows Server 2022<10.0.20348.5622
10.0.20348.5622
Microsoft Windows Server 2025<10.0.26100.33438
10.0.26100.33438

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 10.0.17763.9245Patch KB5122876
  2. Upgrade

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

    Fixed in 10.0.20348.5622Patch KB5122882
  3. Upgrade

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

    Fixed in 10.0.26100.33438Patch KB5122871

Event History

Sep 8, 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·05:18 PM
Data Sourced
via MITRE·05:18 PM
DescriptionSeverity

Frequently Asked Questions

1

Which systems are identified as affected?

The affected software list includes Microsoft Windows 10, Windows Server 2019, Windows Server 2022, and Windows Server 2025.

2

Can an unauthenticated attacker exploit this remotely?

Yes. The vector is network-based and requires no privileges or user interaction, so an unauthorized attacker can attempt exploitation over the network. The listed attack complexity is high.

3

What impact could successful exploitation have?

Successful exploitation can allow remote code execution. The advisory’s metrics indicate high impact to confidentiality, integrity, and availability.

Contact

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