CVE-2026-69809: Windows Active Directory Domain Services Denial of Service Vulnerability

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-08 · updated 2026-10-14
Weakness: CWE-401

Description

Missing release of memory after effective lifetime in Active Directory Domain Services allows an unauthorized attacker to deny service over a network.

Affected products

Microsoft Windows 11: before 10.0.22631.7582 — fixed in 10.0.22631.7582
Microsoft Windows 11: before 10.0.26100.9445 — fixed in 10.0.26100.9445
Microsoft Windows 11 25H2: before 10.0.26200.9445 — fixed in 10.0.26200.9445
Microsoft Windows 11 version 26H1: before 10.0.28000.2954 — fixed in 10.0.28000.2954
Microsoft Windows Server 2022: before 10.0.20348.5622 — fixed in 10.0.20348.5622
Microsoft Windows Server 2025: before 10.0.26100.33438 — fixed in 10.0.26100.33438
Microsoft Windows 11: from 10.0.22631.0 before 10.0.22631.7582 — fixed in 10.0.22631.7582
Microsoft Windows 11: from 10.0.26100.0 before 10.0.26100.9445 — fixed in 10.0.26100.9445
Microsoft Windows 11 25H2: from 10.0.26200.0 before 10.0.26200.9445 — fixed in 10.0.26200.9445
Microsoft Windows 11 version 26H1: from 10.0.28000.0 before 10.0.28000.2954 — fixed in 10.0.28000.2954
Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.5622 — fixed in 10.0.20348.5622
Microsoft Windows Server 2025: from 10.0.26100.0 before 10.0.26100.33438 — fixed in 10.0.26100.33438

How to fix

Upgrade to a fixed version: Microsoft Windows 11 10.0.22631.7582; Microsoft Windows 11 10.0.26100.9445; Microsoft Windows 11 25H2 10.0.26200.9445; Microsoft Windows 11 version 26H1 10.0.28000.2954; Microsoft Windows Server 2022 10.0.20348.5622; Microsoft Windows Server 2025 10.0.26100.33438; Microsoft Windows 11 10.0.22631.7582; Microsoft Windows 11 10.0.26100.9445; Microsoft Windows 11 25H2 10.0.26200.9445; Microsoft Windows 11 version 26H1 10.0.28000.2954; Microsoft Windows Server 2022 10.0.20348.5622; Microsoft Windows Server 2025 10.0.26100.33438. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69809

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