In PHP, Operators are case-sensitive, so use them lowercase. Use as:
version_compare ( $component_version, $vulnerability_version, $vulnerability_operator );lt: Also represented as<. The version of the component is inferior, but not equal, to the vulnerability’s version.le: Also represented as<=. The version of the component is less than or equal to the vulnerability’s version.eq: Also represented as==. The version of the component is the same as the vulnerability’s version.ne: Also represented as!=. The version of the component is different from the vulnerability’s version.gt: Also represented as>. The version of the component is higher than or equal to the vulnerability’s version.ge: Also represented as>=. The version of the component is greater than or equal to the vulnerability’s version.