Heap-based buffer overflow in the Ins_SHZ function in ttinterp.c in FreeType 2.4.3 and earlier allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via a crafted SHZ bytecode instruction, related to TrueType opcodes, as demonstrated by a PDF document with a crafted embedded font.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.