Qt is a software toolkit that simplifies the task of writing andmaintaining GUI (Graphical User Interface) applications for the X WindowSystem. HarfBuzz is an OpenType text shaping engine.A buffer overflow flaw was found in the harfbuzz module in Qt. If a userloaded a specially-crafted font file with an application linked against Qt,it could cause the application to crash or, possibly, execute arbitrarycode with the privileges of the user running the application.(CVE-2011-3193)A buffer overflow flaw was found in the way Qt handled certain gray-scaleimage files. If a user loaded a specially-crafted gray-scale image filewith an application linked against Qt, it could cause the application tocrash or, possibly, execute arbitrary code with the privileges of the userrunning the application. (CVE-2011-3194)Users of Qt should upgrade to these updated packages, which containbackported patches to correct these issues. All running applications linkedagainst Qt libraries must be restarted for this update to take effect.