Code: static int rm_read_multi(AVFormatContext *s, AVIOContext *pb,
                         AVStream *st, char *mime)
{
    int number_of_streams = avio_rb16(pb);
    int number_of_mdpr;
    int i, ret;
    unsigned size2;
    for (i = 0; i<number_of_streams; i++)
        avio_rb16(pb);
    number_of_mdpr = avio_rb16(pb);
    if (number_of_mdpr != 1) {
        avpriv_request_sample(s, "MLTI with multiple (%d) MDPR", number_of_mdpr);
    }
    for (i = 0; i < number_of_mdpr; i++) {
        AVStream *st2;
        if (i > 0) {
            st2 = avformat_new_stream(s, NULL);
            if (!st2) {
                ret = AVERROR(ENOMEM);
                return ret;
            }
            st2->id = st->id + (i<<16);
            st2->codecpar->bit_rate = st->codecpar->bit_rate;
            st2->start_time = st->start_time;
            st2->duration   = st->duration;
            st2->codecpar->codec_type = AVMEDIA_TYPE_DATA;
            st2->priv_data = ff_rm_alloc_rmstream();
            if (!st2->priv_data)
                return AVERROR(ENOMEM);
        } else
            st2 = st;
 
         size2 = avio_rb32(pb);
         ret = ff_rm_read_mdpr_codecdata(s, s->pb, st2, st2->priv_data,
                                        size2, mime);
         if (ret < 0)
             return ret;
     }
    return 0;
}

Vulnerability Type: 
CWE ID: CWE-416
Summary: FFmpeg before commit a7e032a277452366771951e29fd0bf2bd5c029f0 contains a use-after-free vulnerability in the realmedia demuxer that can result in vulnerability allows attacker to read heap memory. This attack appear to be exploitable via specially crafted RM file has to be provided as input. This vulnerability appears to have been fixed in a7e032a277452366771951e29fd0bf2bd5c029f0 and later.
Commit Message: avformat/rmdec: Do not pass mime type in rm_read_multi() to ff_rm_read_mdpr_codecdata()

Fixes: use after free()
Fixes: rmdec-crash-ffe85b4cab1597d1cfea6955705e53f1f5c8a362

Found-by: Paul Ch <paulcher@icloud.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>