Integer overflow in QuickLook, as used in Apple Mac OS X before 10.6.7 and MobileSafari in Apple iOS before 4.2.7 and 4.3.x before 4.3.2, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a Microsoft Office document with a crafted size field in the OfficeArtMetafileHeader, related to OfficeArtBlip, as demonstrated on the iPhone by Charlie Miller and Dion Blazakis during a Pwn2Own competition at CanSecWest 2011.