Rejected reason: Not a vulnerability. Creating a serial queue that overwrites cups-files.conf requires membership in SystemGroups (lpadmin), which is an opt-in cupsd admin role granted by a superuser. No privilege boundary is crossed.

A privilege escalation vulnerability was found in CUPS when used with the cups-filters serial backend. A local user who is a member of the lpadmin group can configure a printer that uses a privileged serial backend. The CUPS scheduler does not restrict the path component of non-file device URIs, so the root-privileged backend can write attacker-controlled print data to an arbitrary file. This can be used to change security-sensitive CUPS configuration and ultimately achieve root code execution. Exploitation requires local lpadmin group membership and a serial backend binary installed with root-only permissions.

cups-filters-1.28.17-10.1 on GA media

Security update for cups-filters