Hello the 90's called
and your Linux system has an insecure telnet server running???
icon for facepalm reaction
I google'd a bit, thinking that maybe there was something out there about telnet and hadoop, and I kept seeing something about port 9000 and not being able to connect to it. Seriously, what's up with the telnet anyway, or is this just being used as a troubleshooting tool (and now, attack vector)? I hope that it's not actually USING a telnet-based command/config thingy but who knows...
/me withholds the 'meme-worthy' reference regarding the number 9000 - dunno if it would actually really apply in this situation.
It might be interesting to know exactly what it is this vulnerability is dealing with, something I can't seem to find with a simple search [and I have no need/desire to install Hadoop in a VM just to see what's up with it].