Multiple buffer overflows in Java SE Development Kit (JDK) and Java Runtime Environment (JRE) 6 Update 12 and earlier allow remote attackers to access files or execute arbitrary code via (1) a crafted PNG image that triggers an integer overflow during memory allocation for display on the splash screen, aka CR 6804996; and (2) a crafted GIF image from which unspecified values are used in calculation of offsets, leading to object-pointer corruption, aka CR 6804997.
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.