I'm wondering what kind of testing you can seriously do in 24 hours. Probably just enough to prove that it doesn't crash your system or wipe any disks within 24 hours. In any case, just because someone has found a bug doesn't mean you have a patch to fix it.
There are classes of bugs, like missing bounds checking, which can be quickly deployed with little risk but the recent /dev/mem kernel bug and the PHP debacle are subtle enough that it can take >24 hours just to determine what the correct fix is. A hastily applied fix can make the problem worse.