Shopify: Subdomain takeover in help.tictail.com pointing to Zendesk (a Shopify acquisition)

Hello, Description: --------------------- The subdomain at https://help.tictail.com has an unclaimed CNAME record tictail.zendesk.com . I checked the username availability in the signup process at zendesk, it was observed that the subdomain is vulnerable to a subdomain takeover which allows an...