This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Apple QuickTime. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.
The specific flaw exists within the processing of MIDI events. An arithmetic overflow in the handling of the sizes of certain events allows for an attacker to overflow a heap buffer. An attacker could use this to execute arbitrary code in the context of the QuickTime process.