Apple has released Security Update 2007-007.
"Security Update 2007-007 is recommended for all users and improves the security of the following components:"
bzip2
CFNetwork
Core Audio
cscope
gnuzip
Kerberos
mDNSResponder
PDFKit
PHP
Quartz Composer
samba
WebKit
WebCore
You can get more info. on Security Update 2007-007 and download it
here or use Software Update.