The security issue itself is described in [1]. Also worth note (at least for me, not used to reading PuTTY's release notes and issue pages) is their class/difficulty/priority breakdown of the issue. I had never seen that pattern before.
The original link also points incidentally to a nice, recently updated survey of cryptography laws around the world. [2]
Tuits come in all shapes and sizes, but round ones are particular prized. It's amazing the amount of work you can accomplish once you get a round tuit.