I don't really think so. The tracker is just a tiny part of the whole Bittorrent setup, and it's only really used by clients to get a list of peers. It's basically just an HTTP call to the tracker, returning a response. The only thing that I can quickly think of is returning some malformed bencode which could cause a memory exhaustion a client written by a novice.

The peer protocol (and variants, like uTP) are much more interesting to attack, and you don't need to host a tracker for that, you can just get peer IPs from trackers or DHT, connect, and do your magic.