This option can be configured in the ossec.conf file.
Online update:
<provider name="nvd">
<enabled>yes</enabled>
<update_from_year>2010</update_from_year>
<update_interval>1h</update_interval>
</provider>
Offline update:
<provider name="nvd">
<enabled>yes</enabled>
<url start="2015" end="2019">http://local_repo/nvd-feed[-].json.gz</url>
<update_interval>1h</update_interval>
</provider>