import re


def is_correct_vector_v3(vector):
    """
    Checks whether CVSSv3 base vector is valid.

    :param vector: base vector of CVSSv3 (string)
    :return: True if valid
    """
    return vector is not None \
        and re.match(r'(CVSS:3\.0/)?AV:[NALP]/AC:[LH]/PR:[NLH]/UI:[NR]/S:[UC]/C:[NLH]/I:[NLH]'
                     r'/A:[NLH](/E:[XUPFH]/RL:[XOTWU]/RC:[XURC])?', vector)