The remote Debian host is missing a security-related update.
Multiple vulnerabilities have been found in the Drupal content management framework. For additional information, please refer to the upstream advisory at https://www.drupal.org/sa-core-2018-001
Upgrade the drupal7 packages. For the oldstable distribution (jessie), this problem has been fixed in version 7.32-1+deb8u10. For the stable distribution (stretch), this problem has been fixed in version 7.52-2+deb9u2.