GStreamer before 1.4.5, as used in Mozilla Firefox before 38.0, Firefox ESR 31.x before 31.7, and Thunderbird before 31.7 on Linux, allows remote attackers to cause a denial of service (buffer over-read and application crash) or possibly execute arbitrary code via crafted H.264 video data in an m4v file.

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.