The host is installed with Mozilla Firefox 4.x before 10.0, Thunderbird 5.0 before 10.0, or SeaMonkey before 2.7 and is prone to information disclosure vulnerability. A flaw is present in the applications, which fail to properly initialize data for image/vnd.microsoft.icon images. Successful exploitation could allow attackers to obtain potentially sensitive information by reading a PNG image that was created through conversion from an ICO image.