Apache WWW server 1.3.1 and earlier allows remote attackers to cause a denial of service (resource exhaustion) via a large number of MIME headers with the same name, aka the "sioux" vulnerability.
http://www.redhat.com/support/errata/rh51-errata-general.html#apache
http://marc.info/?l=bugtraq&m=90286768232093&w=2
http://marc.info/?l=bugtraq&m=90280517007869&w=2