On my 12.3/KDE 4.12.0 system, an update yesterday(12/19) installed Firefox 26.
I have the KDE Wallet 2.1 add-on loaded.
Firefox now sometimes crashes on start-up, reporting kwallet crash.
Other times Firefox runs but kwallet does not seem to be working.
Thanks for info.
It appears to me that KDE Wallet Integration ver 2.2 actually fixes the bug.
Inferred that by noting that I posted against ver 2.1, so enabled 2.2 and it seems to be OK without the workaround.
I only have about 10 minutes of browsing Firefox 26 with it re-enabled, but so far, so good.
YRMV
Nope - kwallet crashed Firefox after 15 minutes!
I am going to leave it disabled for the moment, I would like to understand potential side effects on Firefox implementing his work-around.