I.e. can I find a close enough package in the next nearest distro? Or is it complicated, and compiling from source is better? Or can I grab it from debian?

(This question is about at least Ubuntu 11.10 and 12.10; I'm betting others are hitting this, so if the advice is different depending on exactly which end-of-lifed Ubuntu, it might help to say how!)

P.S. "Upgrade" will not be accepted as an answer ;-) I know that, but sometimes retiring/upgrading/replacing a server takes time, and I'd like to get bash patched first.