Apple has released a Security Update today for Mac OS X Server 10.5, Mac OS X 10.5.8, Mac OS X Server 10.6, Mac OS X 10.6.4 which addresses issues in the following software:
Full details of the changes are detailed on Apple's support site. The update is recommended for all Mac OS X customers.CFNetwork
ClamAV
CoreGraphics
libsecurity
PHP
Samba
Article Link: Apple Releases Security Update 2010-005