The vuln you link to above is fixed in... FP10. Hang on, I think there's a post or two around here some place which details when that version will become available.

All software has bugs, not all those bugs are fixed in shipping products. Nokia chose to go with 9.0.124, for whatever reason, just deal with it. Perhaps Nokia could have gone with a later version of FP9/9.4, but maybe they had more important things to get working first. The vast majority of buyers won't care less about the lack of FP10, they'll be more than happy with FP9.x.

FP10 will become available once it is ready...