Multiple off-by-one errors in libavcodec/vorbisdec.c in FFmpeg before 2.4.2, as used in Google Chrome before 40.0.2214.91, allow remote attackers to cause a denial of service (use-after-free) or possibly have unspecified other impact via crafted Vorbis I data.
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.