Squarespace appears to have a re-direction vulnerability

Site URL: http://bitstop.ca

I was notified by Google today of a vulnerability on my website.

On more investigation I found that the vulnerability is in the squarespace re-direct engine on the old versions of squarespace.

http://bitstop.ca/process/Redirect?url=http://ministeriobetinho.com.br/popup_image1/screenshots.php/kpw/dvq/?island=ed1tvc0qq5v9fy5

You can see the above re-direct sends to an ad site and you can edit the url to really go anyplace you like.

I reached out to Squarespace but wonder if anyone else has seen this issue or is aware of it?