Cross-site scripting (XSS) vulnerability in the Shibboleth authentication module 6.x-4.x before 6.x-4.2 and 7.x-4.x before 7.x-4.2 for Drupal allows remote authenticated users with the "Administer blocks" permission to inject arbitrary web script or HTML via unspecified vectors related to a login link.
https://www.drupal.org/node/2511518
https://www.drupal.org/node/2511280