The newest version of PHP was just released, which addresses several vulnerabilities:
http://www.securityfocus.com/bid/29009
http://www.securityfocus.com/bid/27786
Any code written in PHP is potentially affected by this, depending on which functions you use, so don't forget to update! 
			
			
			
				What functions specifically?  :)
			
			
			
				Dunno, read. :P
Apparently there's an overflow in one of the regexp libraries, that's the only one I noticed.