CVE-2026-85319: Active Directory Federation Services (AD FS) Denial of Service Vulnerability
Active Directory Federation Services (AD FS) Denial of Service Vulnerability
Other sources
Allocation of resources without limits or throttling 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 6.3.9600.23470Patch KB5126836 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.20348.5761Patch KB5126655 - 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 10.0.26100.33650Patch KB5126646 - 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 10.0.17763.9376Patch KB5126651
Event History
Frequently Asked Questions
Who can exploit this issue?
An unauthorized attacker can exploit it remotely over the network. No privileges or user interaction are required according to the supplied severity vector.
What is the expected impact?
The vulnerability can allow denial of service against AD FS through resource allocation without limits or throttling. The supplied vector indicates availability impact only, with no stated confidentiality or integrity impact.
Which systems should be assessed?
Assess AD FS deployments on the listed Microsoft Windows versions: Windows 10 and Windows Server 2012, 2012 R2, 2016, 2019, 2022, and 2025. The provided data does not identify affected AD FS versions or configuration prerequisites.