A new Security Update has been released for Mac OS X Snow Leopard named:
According to the OSXDaily article, the update patches "several potential exploits" and that one of the said exploits is similar to the PDF exploit seen in iOS - it's that security hole which allowed easy jailbreaking via jailbreakme.com.
iOS has been patched recently via iOS 4.0.2 and that makes it patched earlier than Mac OS X. It looks indeed like iOS and Mac OS X share a lot more than we've come to expect and that includes security holes...
So it's time to click on that juicy little Apple icon on the menubar, then run Software Update. Or alternatively, you can download the update in .dmg format through the link provided above.