It was identified that if a cross-cluster API key https://www.elastic.co/guide/en/elasticsearch/reference/8.14/security-api-create-cross-cluster-api-key.html#security-api-create-cross-cluster-api-key-request-body restricts search for a given index using the query or the field_security parameter, and the same cross-cluster API key also grants replication for the same index, the search restrictions are not enforced during cross cluster search operations and search results may include documents and terms that should not be returned.
This issue only affects the API key based security model for remote clusters https://www.elastic.co/guide/en/elasticsearch/reference/8.14/remote-clusters.html#remote-clusters-security-models that was previously a beta feature and is released as GA with 8.14.0