The mod_proxy_ajp module in the Apache HTTP Server before 2.2.21, when used with mod_proxy_balancer in certain configurations, allows remote attackers to cause a denial of service (temporary "error state" in the backend server) via a malformed HTTP request.
http://www.securityfocus.com/bid/49616
http://httpd.apache.org/security/vulnerabilities_22.html#2.2.21
http://www.securitytracker.com/id?1026054
http://secunia.com/advisories/46013
http://www.apache.org/dist/httpd/Announcement2.2.html
http://community.jboss.org/message/625307
http://www.redhat.com/support/errata/RHSA-2011-1391.html
http://marc.info/?l=bugtraq&m=131731002122529&w=2
http://marc.info/?l=bugtraq&m=132033751509019&w=2
http://www.mandriva.com/security/advisories?name=MDVSA-2011:168
http://support.apple.com/kb/HT5130
http://lists.apple.com/archives/security-announce/2012/Feb/msg00000.html
http://www.oracle.com/technetwork/topics/security/cpujuly2013-1899826.html
https://exchange.xforce.ibmcloud.com/vulnerabilities/69804
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A18154
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A14941
http://rhn.redhat.com/errata/RHSA-2012-0543.html
http://rhn.redhat.com/errata/RHSA-2012-0542.html
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E