CVE-2026-85324: Active Directory Federation Services (AD FS) Denial of Service Vulnerability
Active Directory Federation Services (AD FS) Denial of Service Vulnerability
Other sources
Memory allocation with excessive size value in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.2.9200.26434Patch KB5126835 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.17763.9376Patch KB5126651 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.3.9600.23470Patch KB5126836 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.14393.9612Patch KB5126868 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26100.33650Patch KB5126646 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.20348.5761Patch KB5126655
Event History
Frequently Asked Questions
Does exploitation require authentication or user interaction?
No. The severity vector indicates that no privileges and no user interaction are required.
Which systems should be prioritized for review?
Review AD FS deployments on Microsoft Windows 10 and Windows Server 2012, 2012 R2, 2016, 2019, 2022, and 2025. The provided data identifies AD FS as the affected component, rather than all installations of those operating systems.
What is the expected impact if exploitation succeeds?
The stated impact is denial of service through excessive memory allocation. The supplied severity vector indicates high availability impact, with no stated confidentiality or integrity impact.