A critical vulnerability in Blogger (Google Service) could be used by an attacker to get administrator privilege over any blogger account (Permission Issue) The vulnerability mentioned here has been confirmed patched by the Google Security Team very fast. To make a successful attack (become administrator), an attacker must add himself first as a author on the victim’s blogger account, To perform the next step that will add himself as an administrator on the. victim account. The attacker uses the. invite author options in blogger (add authors): The server. checks the first blogid value and executes the second blogid. value of the attacker.
Source: https://thehackernews.com/2011/03/bloggercom-vulnerability-gaining.html