Integer signedness error in psaux/t1decode.c in FreeType before 2.4.6, as used in CoreGraphics in Apple iOS before 4.2.9 and 4.3.x before 4.3.4 and other products, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted Type 1 font in a PDF document, as exploited in the wild in July 2011.