[sub.wordpress.com] - XSS when adjust block Poll - Confirmation Message - On submission:Redirect to another webpage - Redirect address:[xss_payload]

## Summary: Dear Wordpress Team, Today when I tried to create a post with block "Poll" and I have found at Poll Block -> Confirmation Message -> On submission:Redirect to another webpage and Redirect address:[xss_payload] At Redirect address line, I can save the ```blocked:alert(document.cookie)``` as an URL webpage after submit a poll. And when an authenticated wordpress user submitted a poll, their cookies may stolen by attacker ## Platform(s) Affected: https://subdomain.wordpress.com ## Steps To Reproduce: 1- Logged in your wordpress website and create a post with block Poll, fill question and some choices {F1104221} 2- Adjust Poll Block, Confirmation Message -> On submission:Redirect to another webpage and Redirect address:blocked:alert(document.cookie) then click Update/Publish your post {F1104220} 3- Go to your created poll and Submit, you will see xss popup {F1104222} You can see video PoC below for the steps: {F1104231} ## Impact Steal cookies