Multiple stack-based buffer overflows in the cff_decoder_parse_charstrings function in the CFF Type2 CharStrings interpreter in cff/cffgload.c in FreeType before 2.4.2, as used in Apple iOS before 4.0.2 on the iPhone and iPod touch and before 3.2.2 on the iPad, allow remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via crafted CFF opcodes in embedded fonts in a PDF document, as demonstrated by JailbreakMe. NOTE: some of these details are obtained from third party information.
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.