keycloak: org.keycloak.protocol.oidc: unvalidated cross-origin messages in checkLoginIframe leads to DDoS

A flaw was found in Keycloak's OIDC component in the "checkLoginIframe," which allows unvalidated cross-origin messages. This flaw allows attackers to coordinate and send millions of requests in seconds using simple code, significantly impacting the application's availability without proper origi...