Missing authorization checks in the Backend Routing of TYPO3 CMS versions 9.0.0‑9.5.54, 10.0.0‑10.4.53, 11.0.0‑11.5.47, 12.0.0‑12.4.36, and 13.0.0‑13.4.17 allow backend users to directly invoke AJAX backend routes without having access to the corresponding backend modules.