Drupal 7 has an Open Redirect vulnerability. For example, a user could be tricked into visiting a specially crafted link which would redirect them to an arbitrary external URL.

For Debian 8 Jessie, this problem has been fixed in version 7.32-1+deb8u18.

We recommend that you upgrade your drupal7 packages.

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS