Postfix Configuration: How to restrict use of CC

I have configured postfix on my server.

telnet mydomain.com 25
helo validdomain.com
mail from: validaddress@validdomain.com
rcpt to: validuser@mydomain.com
data
From: validaddress@validdomain.com
To: validuser@mydomain.com
CC: user1@domain1.com,user2@domain2.com
Subject: Testing postfix
Message body

When I run this test, the email is delivered to valid user but also my server shoots an email to user1 and user2.
I have implemented client, helo and recipient restrictions as below.
How do I prevent the malicious use of CC as described here?
Thank you


Snap of main.cf
-------------------
smtpd_client_restrictions = permit_mynetworks,
reject_invalid_hostname,
reject_rbl_client zen.spamhaus.org,
reject_unknown_client,
permit

smtpd_helo_restrictions = permit_mynetworks,
check_helo_access hash:/etc/postfix/helo_access,
reject_unauth_pipelining,
reject_non_fqdn_hostname,
reject_invalid_hostname,
warn_if_reject reject_unknown_hostname,
permit

smtpd_recipient_restrictions = reject_non_fqdn_sender,
reject_non_fqdn_recipient,
reject_non_fqdn_hostname,
reject_invalid_hostname,
permit_mynetworks,
reject_unauth_pipelining,
reject_unknown_sender_domain,
reject_unknown_recipient_domain,
reject_unauth_destination,
reject_unknown_client,
permit

smtpd_sender_restrictions = permit_mynetworks,
reject_non_fqdn_sender,
reject_unknown_sender_domain,
reject_unknown_address