Apple has released Security Update 2010-006 Snow Leopard (http://support.apple.com/kb/DL1105). The company says it’s recommended for all users and improves the security of Mac OS X.
Security Update 2010-006 Snow Leopard is a 1.93MB download that requires Mac OS X 10.6.4. You can obtain it via the Software Update component of the Mac OS X Systems Preferences app.