A vulnerability in Keycloak's SAML broker endpoint allows unauthorized access due to improper validation of encrypted SAML assertions when the overall SAML response is not signed. An attacker with a valid signed SAML assertion can craft a malicious SAML response to inject an encrypted assertion for an arbitrary principal, potentially leading to unauthorized access and information disclosure. This issue affects multiple versions of the Keycloak SAML adapter core and has a high severity rating.