This indicates an attack attempt to exploit a Privilege Escalation vulnerability in the Apple CUPS.
The vulnerability is due to an error when the vulnerable application handles a malicious request. A remote attacker may be able to exploit this to elevate their privileges to achieve root access via a crafted HTTP request.
Apple Computer Common UNIX Printing System (CUPS) prior to 2.0.3
Privilege Escalation: Remote attackers can leverage their privilege on the vulnerable systems.
Apply the most recent upgrade or patch from the vendor.