The JPEG 2000 codec (jp2.c) in OpenJPEG before 1.5 allows remote attackers to execute arbitrary code via a crafted palette index in a CMAP record of a JPEG image, which triggers memory corruption, aka "out-of heap-based buffer write."
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.