Multiple vulnerabilities were found in Qt image format handling of BMP, ICO and GIF files. The issues exposed included denial of service and buffer overflows leading to heap corruption. It is possible the latter could be used to perform remote code execution.
This update can be installed with the "yum" update program. Use su -c 'yum update qt5-qtbase' at the command line. For more information, refer to "Managing Software with yum", available at http://docs.fedoraproject.org/yum/.