This is a remote code execution vulnerability. Because Symantec use a filter driver to intercept all system I/O, just emailing a file to a victim or sending them a link is enough to exploit it.
On Linux, Mac and other UNIX platforms, this results in a remote heap overflow as root in the Symantec or Norton process. On Windows, this results in kernel memory corruption, as the scan engine is loaded into the kernel (wtf!!!), making this a remote ring0 memory corruption vulnerability - this is about as bad as it can possibly get.