Trojans are different from viruses because they can lurk in PCs without anyone noticing and can spy on the computer user's activities then send this information back anywhere in the world.
A vulnerability like this opens the door for hackers to spy on your sensitive information. Users running the affected software should upgrade as soon as possible.
A vulnerability like this opens the door for hackers to spy upon your sensitive information. Not protecting yourself against this problem is like leaving your front door open when you pop down the shops, and expecting to find that no-one has stolen your belongings.