This module enables you to integrate the site with the Google Tag Manager (GTM) application.
The module doesn't have the "restrict access" flag on the "administer google_tag_container" permission. A user with this permission can load a GTM container that completely changes the page or inserts malicious JS, resulting in a cross site scripting vulnerability.
This vulnerability is mitigated by the fact that an attacker must have a role with the aforementioned permission.