Apple today released Security Update 2010-001 is recommended for all users and improves the security of Mac OS X.
Security Update 2010-001 is available for various versions of Mac OS X via Software Update and also via standalone installers.
More info and download links:
• Security Update 2010-001 (Snow Leopard) – 21.90 MB
• Security Update 2010-001 Client (Leopard) – 159.58 MB
• Security Update 2010-001 Server (Leopard) – 248.11 MB