Hello Andy,
the info is no longer available but the list of known affected versions it is:
they all are 11.1.x versions that are very old now.
a CPUHOG is when a process uses the CPU for more then a threshold time (in modern routers it is 2000 msecs)
I guess the problem for RIP can happen when the number of routes is high (they are sent out on every update).
If the time is just a little more then 2000 msecs the problem is not really serious but when a process holds the cpu for very long time the watchdog process can trigger a router reload
Hope to help
Giuseppe