Incomplete blacklist vulnerability in CoreTypes in Apple Mac OS X before 10.5.3 allows user-assisted remote attackers to execute arbitrary code via an (1) Automator, (2) Help, (3) Safari, or (4) Terminal content type for a downloadable object, which does not trigger a "potentially unsafe" warning message in (a) the Download Validation feature in Mac OS X 10.4 or (b) the Quarantine feature in Mac OS X 10.5.