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://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=168072
http://securitytracker.com/id?1012811
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A9774