Summary
Impact: Spoofing. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
How could an attacker exploit this vulnerability?
An unauthenticated attacker could relay a validly signed SAML response intended for a different endpoint to an affected AD FS endpoint. Successful exploitation could allow the attacker to create an unauthorized session and obtain tokens. No user interaction is required.
Security updates
6.2.9200.26434 — https://support.microsoft.com/help/5126835
6.3.9600.23470 — https://support.microsoft.com/help/5126836
10.0.14393.9612 — https://support.microsoft.com/help/5126868
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
Vulnerabilities 1
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Critical 9.1
Active Directory Federation Services (AD FS) Spoofing Vulnerability
Improper verification of cryptographic signature in Active Directory Federation Services (AD FS) allows an unauthorized attacker to perform spoofing over a network.
Revision history
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#1
Information published.
References
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CVE-2026-96252 Active Directory Federation Services (AD FS) Spoofing Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-96252
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Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
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Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
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Common Vulnerability Scoring System
https://www.first.org/cvss