def cve_is_about_system(cpe_type):
    """
    Determines whether CVE is about system.

    :param cpe_type: One of {'a', 'o', 'h'} = application, operating system,
    hardware
    :return: true if CVE is about system.
    """
    return ('o' in cpe_type or 'h' in cpe_type) and 'a' not in cpe_type