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 way Shockwave handles KEY* elements in a Director file. The Shockwave player will allocate memory with a size taken from the Shockwave file but will always copy a few bytes into that allocation. KEY* sizes smaller then 4 will therefore cause an overwrite of the allocation. By cleverly crafting the input file, an attacker can leverage this to execute remote code under the context of the current user.