An issue was discovered in Centreon before 18.10.8, 19.04.5, and 19.10.2. It provides sensitive information via an unauthenticated direct request for api/external.php?object=centreon_metric&action=listByService.
https://github.com/centreon/centreon/pull/8021
https://documentation.centreon.com/docs/centreon/en/latest/release_notes/centreon-19.10/index.html