How to stop "A potentially dangerous Request.Path" with "<"

Hello,

I've been getting "A potentially dangerous Request.Path value was detected from the client (<)." recently and it is causing the application pools in IIS to stop working. 

The url they are trying to pass through is similar to this: 

https://test.com:443/cds/pubs/bib/<my_tag_9ac1214b650a30718aced57527fd64c4/> 

If users can past this URL at any point on my site, how can I stop it from constantly stopping my site and still being safe from SQL injection, Cross Site Scripting or some other vulnerability?

Can I encode it before the page is processed so "<" becomes "&lt;"?  That way this will not be considered a dangerous Request.Path.

Thank you