A flaw exists in the org.keycloak.broker.oidc package where the OIDC broker incorrectly synchronizes the email_verified claim. When an OIDC identity provider is configured with trustEmail=true and the userinfo endpoint is enabled, Keycloak retrieves the email address from the userinfo response but retrieves the email_verified status exclusively from the id_token. The root cause is a lack of validation ensuring that the email_verified claim in the id_token actually refers to the email address returned by the userinfo endpoint. If these two sources return different email addresses, the id_token's email_verified=true claim is blindly applied to the userinfo email. Exploitation Conditions: The OIDC identity provider must have trustEmail set to true (non-default).

The userinfo endpoint must be enabled (default).

The attacker must control or have compromised the upstream OIDC provider.

Concrete Impact: Mark arbitrary email addresses as verified in the Keycloak database.

Bypass email-based security controls or verification workflows.

Potential account takeover if the application relies solely on the email_verified flag from the IdP to link accounts.

A flaw exists in the org.keycloak.broker.oidc package where the OIDC broker incorrectly synchronizes the email_verified claim. When an OIDC identity provider is configured with trustEmail=true and the userinfo endpoint is enabled, Keycloak retrieves the email address from the userinfo response but retrieves the email_verified status exclusively from the id_token. The root cause is a lack of validation ensuring that the email_verified claim in the id_token actually refers to the email address returned by the userinfo endpoint. If these two sources return different email addresses, the id_token's email_verified=true claim is blindly applied to the userinfo email. Exploitation Conditions: The OIDC identity provider must have trustEmail set to true (non-default).

The userinfo endpoint must be enabled (default).

The attacker must control or have compromised the upstream OIDC provider.

Concrete Impact: Mark arbitrary email addresses as verified in the Keycloak database.

Bypass email-based security controls or verification workflows.

Potential account takeover if the application relies solely on the email_verified flag from the IdP to link accounts.

Ein Angreifer kann mehrere Schwachstellen in Keycloak ausnutzen, um Informationen offenzulegen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren oder erweiterte Berechtigungen zu erlangen.