ZITADEL is an open source identity management platform. Prior to 4.15.1, ZITADEL's event store validation can retain the original resource owner for a deleted user identifier, causing a later user recreated with the same identifier in another organization to be provisioned under the original organization and exposed to that organization's administrator. This issue is fixed in version 4.15.2.

ZITADEL: Cross-Tenant User Leakage via Recycled Identifiers