CVE-2025-21193

Summary

CVE-2025-21193 is a newly discovered vulnerability affecting Microsoft Active Directory Federation Servers. This issue allows an attacker to perform spoofing attacks by manipulating the response from the server during the Single Sign-On (SSO) process. The attacker can trick the server into believing that it is communicating with a trusted entity, enabling unauthorized access to protected resources. This vulnerability poses a significant risk to organizations that rely on Active Directory Federation Servers for authentication and authorization. Microsoft has released a patch to address this issue and urges administrators to apply it as soon as possible to mitigate the risk.

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