httputils.rb in WEBrick in Ruby 1.8.1 and 1.8.5, as used in Red Hat Enterprise Linux 4 and 5, allows remote attackers to cause a denial of service (CPU consumption) via a crafted HTTP request. NOTE: this issue exists because of an incomplete fix for CVE-2008-3656.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10250
https://bugzilla.redhat.com/show_bug.cgi?id=470252
http://www.redhat.com/support/errata/RHSA-2008-0981.html