The admin console's event viewer displays logged event data inside of 
<pre></pre> tags. An attack string like 
"</pre><script>alert('hi')</script>" in any place across Enterprise 
Search that will cause an error, like instead of a number or for the 
username on the login page or through the new Federated Authentication, 
will then be stored in the event log. The payload will execute each time 
someone view the logs in the admin console.

Tested version: 11.2.2
Product URL: 
https://www.hyland.com/en/platform/product-suite/enterprise-search