Im pretty sure that vulnerability (among several others) was introduced with 10.7 Lion.
Snow Leopard, OS X 10.6.8, is one of the fastest, stablest, most secure operating systems ever released.
I would recommend that any Mac capable of running Snow Leopard, should be running Snow Leopard. My 2007 MBP certainly is.
THIS.
So by a stroke of unbelievable luck I found my copy of Snow Leopard from the release day I went to go buy it at the Apple Store. Version 10.6
I erased the HDD and installed SL to 10.6
It ran smoothly with hardly any hiccups minus YouTube wouldn't play videos saying it needed to update Adobe flash but the Abode site said 10.6 wasn't supported anymore. Then I did a software update check and it recommended a few updates, mainly 10.6.8; to which I upgraded and now ALL of my applications run smoothly and great. Even Safari doesn't lag at all. I gotta say, for a 6 year old machine with only 4GB's of RAM, i'm in love all over again. Even the battery life is much more improved.
One issue though, I restored my iPhone 4 through iTunes and then downloaded Pangu to re-jailbreak my phone but the Pangu app kept crashing without ever opening. Upong perusing the forums I noticed this was a common issue and Pangu begins to work again on 10.7 Lion
I gotta say, and ask... I'm tempted to see how 10.7 Lion is. It's a simple download and if I don't like it I always have this 10.6 disc here with me.
I feel the biggest issue i'll come across my using 10.6.8 is coming across some random app every once in a while that is no longer supported or useable, which is admittedly a pain... BUT BOY IS 'SPACES' SEXY! Spaces still have to be one of my favorite OSX features.
It is not as secure as you make out. Nor is it especially stable or fast. I had memory issues caused by Snow Leopard (they weren't there in Lion or Leopard) meaning the system would page to disk unnecessarily. Only solved by a reboot.
So admittedly, this scares me and makes me wonder if i'll encounter the same in 10.6.8;the only frame of reference I have with these systems are old memories of me using these updates and remembering Snow Leopard being sublime and consistent. I believe it came out the same year my 09' MBP did too (made for each other). I remember either Lion or Mountain Lion messing up a lot of my files and having numerous lagging or freezing pages and apps.