Akshay AKA 0z0n3 claimed that he have discovered a Persistent XSS vulnerability in blogspot.com. He managed to inject the xss vector in his own blogger dashboard. He is sure it is not template page(usually templates allow bloggers to inject scripts ).
He used one of the following xss vector:
After injecting, he didn't get a pop-up but after some minutes he started getting pop-ups. He reported about the vulnerability to Google Security team. The vulnerability is not rewarded by Google.
"Thank you for your note. We took a look at the XSS issue you reported. Unfortunatley, the XSS issues is executing on the blogspot domain and not blogger.com. We come some of these scenarios here.