Integer overflow in the gst_vorbis_tag_add_coverart function (gst-libs/gst/tag/gstvorbistag.c) in vorbistag in gst-plugins-base (aka gstreamer-plugins-base) before 0.10.23 in GStreamer allows context-dependent attackers to execute arbitrary code via a crafted COVERART tag that is converted from a base64 representation, which triggers a heap-based buffer overflow.
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.