A flaw was found in the first-broker-login flow of the keycloak-services component. This component handles the initial authentication and account linking when a user logs in via an external identity provider. The issue allows an attacker to register a matching username on an external provider to trigger a collision in Keycloak, which results in the legitimate user being locked out of their account.

A flaw was found in the first-broker-login flow of the keycloak-services component. This component handles the initial authentication and account linking when a user logs in via an external identity provider. The issue allows an attacker to register a matching username on an external provider to trigger a collision in Keycloak, which results in the legitimate user being locked out of their account.

keycloak-services: keycloak-services: Privilege escalation via impersonation role allows takeover of realm administrator accounts keycloak-services: keycloak-services: SAML Redirect DEFLATE helpers leak native zlib state keycloak-services: keycloak-services: Broker-originated username collision causes account lockout keycloak-services: keycloak-services: Incomplete fix for arbitrary filesystem path probing via keystore parameters io.netty/netty-handler: Netty: TLS hostname verification bypass via OpenSSL client path misconfiguration keycloak-services: keycloak-services: Incomplete fix for CVE-2026-15573 allows policy enforcer bypass via percent-encoded URI segments keycloak-services: keycloak-services: unauthenticated DoS via unbounded locale caching

Affected: Ubuntu:24.04:LTS: python-keycloak, Ubuntu:26.10: python-keycloak

A flaw was found in the first-broker-login flow of the keycloak-services component. This component handles the initial authentication and account linking when a user logs in via an external identity provider. The issue allows an attacker to register a matching username on an external provider to trigger a collision in Keycloak, which results in the legitimate user being locked out of their account.