static void mov_read_chapters(AVFormatContext *s)
{
    MOVContext *mov = s->priv_data;
    AVStream *st = NULL;
    MOVStreamContext *sc;
    int64_t cur_pos;
    int i;

    for (i = 0; i < s->nb_streams; i++)
        if (s->streams[i]->id == mov->chapter_track) {
            st = s->streams[i];
            break;
        }
    if (!st) {
        av_log(s, AV_LOG_ERROR, "Referenced QT chapter track not found\n");
        return;
    }

    st->discard = AVDISCARD_ALL;
    sc = st->priv_data;
    cur_pos = avio_tell(sc->pb);

    for (i = 0; i < st->nb_index_entries; i++) {
        AVIndexEntry *sample = &st->index_entries[i];
        int64_t end = i+1 < st->nb_index_entries ? st->index_entries[i+1].timestamp : st->duration;
        uint8_t *title;
        uint16_t ch;
        int len, title_len;

        if (avio_seek(sc->pb, sample->pos, SEEK_SET) != sample->pos) {
            av_log(s, AV_LOG_ERROR, "Chapter %d not found in file\n", i);
            goto finish;
        }

        len = avio_rb16(sc->pb);
        if (len > sample->size-2)
            continue;
        title_len = 2*len + 1;
        if (!(title = av_mallocz(title_len)))
            goto finish;

        if (!len) {
            title[0] = 0;
        } else {
            ch = avio_rb16(sc->pb);
            if (ch == 0xfeff)
                avio_get_str16be(sc->pb, len, title, title_len);
            else if (ch == 0xfffe)
                avio_get_str16le(sc->pb, len, title, title_len);
            else {
                AV_WB16(title, ch);
                if (len == 1 || len == 2)
                    title[len] = 0;
                else
                    avio_get_str(sc->pb, INT_MAX, title + 2, len - 1);
            }
        }

        avpriv_new_chapter(s, i, st->time_base, sample->timestamp, end, title);
        av_freep(&title);
    }
finish:
    avio_seek(sc->pb, cur_pos, SEEK_SET);
}

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.