Heap-based buffer overflow in the nestegg_track_codec_data function in Mozilla Firefox before 41.0 and Firefox ESR 38.x before 38.3 allows remote attackers to execute arbitrary code via a crafted header in a WebM video.
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.