High MSRC-CVE-2026-85324 1 CVE

Active Directory Federation Services (AD FS) Denial of Service Vulnerability

Published Oct 13, 2026 · Updated Oct 13, 2026

Vendor: Microsoft

Summary

Impact: Denial of Service. Microsoft rating: Important. Not known to be exploited — Exploitation Unlikely. Customer action: Required.

Details

Security updates
10.0.17763.9376 — https://support.microsoft.com/help/5126651
10.0.20348.5761 — https://support.microsoft.com/help/5126655
10.0.26100.33650 — https://support.microsoft.com/help/5126646
10.0.14393.9612 — https://support.microsoft.com/help/5126868
6.2.9200.26434 — https://support.microsoft.com/help/5126835
6.3.9600.23470 — https://support.microsoft.com/help/5126836

Vulnerabilities 1

High 7.5

CVE-2026-85324

Active Directory Federation Services (AD FS) Denial of Service Vulnerability

Memory allocation with excessive size value in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.

Microsoft Windows Server 2019 Windows Server 2019 (Server Core installation) Windows 10 Version 1809 Windows

Oct 13, 2026

Revision history

2026-10-13 #1
Information published.

References

CVE-2026-85324 Active Directory Federation Services (AD FS) Denial of Service Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85324
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss