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 library's support of SVG markers. When updating a marker, the application will duplicate the reference of an object without updating it's reference count. When freeing this object, a use-after-free vulnerability can be made to occur. This can be leveraged by a remote attacker to execute code under the context of the user running the application.
Patch Availability:
Apple has issued an update to correct this vulnerability. More details can be found at: http://support.apple.com/kb/HT4808
