The Code Signing feature in Apple OS X before 10.10 does not properly handle incomplete resource envelopes in signed bundles, which allows remote attackers to bypass intended app-author restrictions by omitting an execution-related resource.
Apple Security Advisory 2014-10-16-1 - OS X Yosemite v10.10 is now available and addresses 802.1X, AFP file server, Apache, App Sandbox, and various other vulnerabilities.