The tt_sbit_decoder_load_image function in sfnt/ttsbit.c in FreeType before 2.5.4 does not properly check for an integer overflow, which allows remote attackers to cause a denial of service (out-of-bounds read) or possibly have unspecified other impact via a crafted OpenType font.
Improper Restriction of Operations within the Bounds of a Memory Buffer The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.