CUPS, the Common UNIX Printing System, is the printing service stack used on many Unix-like systems, including macOS. It handles printer discovery, job spooling, filters, and communication between applications and printer back ends. Because it often runs with elevated permissions or relies on privileged helper components, it sits near sensitive file, device, and process boundaries.
In security, CUPS matters because a flaw in its parsing, file handling, or helper logic can become a local privilege-escalation path. Attackers with a foothold may try to abuse a CUPS bug to write files, alter configuration, or reach root-level code execution. Defenders should treat CUPS like other privileged infrastructure: keep it patched, limit local code execution, monitor for unusual print jobs or helper activity, and reduce the attack surface by disabling unneeded print services. Even a routine service can become a high-value target when trust checks fail.