About half of the vulnerabilities repaired by Apple are in open-source applications, including Apache, Clam AV, MIT Kerberos 5, and PHP. The other half were found in Apple applications or components. While Apple doesn't characterize the vulnerabilities by severity, a significant number of them could allow a remote attacker to execute arbitrary code on the affected system.
Security Update 2008-002 can be downloaded automatically by way of Apple’s Software Update tool or manually from the Apple Downloads site. Depending on the version, the update runs between 50MB and 108MB in size.