GHSL-2024-280: Gstreamer Use-After-Free read in Matroska CodecPrivate

GStreamer is a library for constructing graphs of media-handling components. An Use-After-Free read vulnerability has been discovered affecting the processing of CodecPrivate elements in Matroska streams. In the GST_MATROSKA_ID_CODECPRIVATE case within the gst_matroska_demux_parse_stream function, a data chunk is allocated using gst_ebml_read_binary. Later, the allocated memory is freed in the gst_matroska_track_free function, by the call to g_free (track->codec_priv). Finally, the freed memory is accessed in the caps_serialize function through gst_value_serialize_buffer. The freed memory will be accessed in the gst_value_serialize_buffer function. This results in a UAF read vulnerability, as the function tries to process memory that has already been freed. This vulnerability is fixed in 1.24.10.