The process scheduler in the Linux kernel 2.6.16 gives preference to "interactive" processes that perform voluntary sleeps, which allows local users to cause a denial of service (CPU consumption), as described in "Secretly Monopolizing the CPU Without Superuser Privileges."
The Red Hat Security Response Team has rated this issue as having moderate security impact.
The risks associated with fixing this bug are greater than the moderate severity security risk. We therefore currently have no plans to fix this flaw in Red Hat Enterprise Linux 3, 4, 5, and Red Hat Enterprise MRG.