Hacking Cisco IOS

I'm looking into hacking a Cisco router running IOS and I need some guidance. Not really sure how to go about doing this, although I've searched for known vulnerabilities online and found these vulnerabilities online.

My goal is to either cause the router to DOS its clients or better yet gain access to the router. I don't have much experience with router hacking and Cisco's IOS so I'd appreciate all the help I can get.