A missing access control check when invoking various modify methods in the XML‑RPC API of Revive Adserver 6.0.6 and earlier. The API allowed entities to be reassigned to different parent entities, leading to inconsistent ownership relationships. This issue was exploitable only in combination with CVE‑2026‑34917 or with third‑party API extensions that expose API functionality to low‑privileged users. Access control checks have been added to validate access to parent entities in the API modify methods.