The Universal CDN system allows you to add several CNAME records for each zone and to point them to the given domain name of your zone.
To add a CNAME record to your CDN zone, follow the steps outlined below:
1. Log in to the Universal CDN Control Panel at my.ucdn.com.
2. Navigate to the My Zones tab located in the top left corner.
3. Click on the cogwheel icon 
next to the CDN zone to which CNAME(s) will be added.
4. Navigate to the Main Settings and scroll down to the Domain name (CNAME) section.
5. Check the box next to I want to add more domains (CNAMEs) to reference my files.
6. Enter the CNAME(s) and click on the Save Changes button.
IMPORTANT! Before adding it to the UCDN control panel, the CNAME record should be properly configured within the DNS manager of your domain. It needs to be mapped to the CDN zone domain to which will be added (e.g. 11011-10.b.cdn12.com). DNS entry example:
Type: CNAME Host: foo.yourdomain.tld Destination Value: 11011-10.b.cdn12.com Limit Access Using a Secret Key