CVE-2026-18215 Keycloak-services: keycloak-services: microsoft external access-token exchange bypasses configured tenant

Keycloak provides a way to let users log in using Microsoft accounts while restricting access to a specific organization tenant. A flaw was discovered where this restriction is ignored when using the token exchange feature. This means an attacker with a valid Microsoft token from a completely...

CVE-2026-18215

Keycloak-security issue: Microsoft accounts login with tenant restriction can be bypassed via token exchange. A valid Microsoft token from a different organization could grant access to the Keycloak realm, exposing data or enabling unauthorized actions. Affected component is Keycloak’s Microsoft ...