static int setup_partitions(VP8Context *s, const uint8_t *buf, int buf_size)
{
    const uint8_t *sizes = buf;
    int i;
    int ret;

    s->num_coeff_partitions = 1 << vp8_rac_get_uint(&s->c, 2);

    buf      += 3 * (s->num_coeff_partitions - 1);
    buf_size -= 3 * (s->num_coeff_partitions - 1);
    if (buf_size < 0)
        return -1;

    for (i = 0; i < s->num_coeff_partitions - 1; i++) {
        int size = AV_RL24(sizes + 3 * i);
        if (buf_size - size < 0)
            return -1;

        ret = ff_vp56_init_range_decoder(&s->coeff_partition[i], buf, size);
        if (ret < 0)
            return ret;
        buf      += size;
        buf_size -= size;
    }
    return ff_vp56_init_range_decoder(&s->coeff_partition[i], buf, buf_size);
}

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.