The GIF encoder in Byzanz allows remote attackers to cause a denial of service (out-of-bounds heap write and crash) or possibly execute arbitrary code via a crafted Byzanz debug data recording (ByzanzRecording file) to the byzanz-playback command.
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.