Apple has release its second security update since the release of Panther. Security Update 2003-11-04 addresses a vulnerability with the OS X Terminal application. From Apple:
Security Update 2003-11-04 addresses a potential vulnerability with the Terminal application in Mac OS X v10.3 and Mac OS X Server v10.3 that could allow unauthorized access to a system.
Apple has not posted any other information at this time, but we will update this post when more information becomes available.
You must use the Software Update application in OS X to install Security Update 2003-11-04. The update weighs in at 712 KB