The is_path_absolute function in scheduler/client.c for the daemon in CUPS before 1.1.23 allows remote attackers to cause a denial of service (CPU consumption by tight loop) via a "..\.." URL in an HTTP request.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A9774
http://www.redhat.com/support/errata/RHSA-2005-772.html
http://www.cups.org/str.php?L1042+P0+S-1+C0+I0+E0+Q1042