The GDPR cookies module for Backdrop CMS (before 1.x-1.3.5) doesn't sufficiently protect visitors from Cross Site Scripting (XSS) if a malicious value has been provided for the optional 'Info content' field for the YouTube service. This is mitigated by the fact that an attacker must have a role with the permission "Create a GDPR Cookies Service" or "Edit any GDPR Cookies Service" and a site must have added a YouTube service as configuration.
Analyzing vulnerability vectors…