self signed certificates are issued by default to invalid Common Name

When I create new virtual server server4.example.com the new self-signed certificate is issued to Common Name *.server4.example.com. This means that this certificate is valid for www.server4.example.com and something.server4.example.com, but not for server4.example.com.

Firefox says:

server4.example.com uses an invalid security certificate. The certificate is not trusted because it is self-signed. The certificate is not valid for the name server4.example.com. Error code: SEC_ERROR_UNKNOWN_ISSUER

What is expected: the certificate to be valid for www.server4.example.com and server4.example.com (or also for *.server4.example.com, in addition to www and non-www).