The xmlrpc extension in PHP 5.3.1 does not properly handle a missing methodName element in the first argument to the xmlrpc_decode_request function, which allows context-dependent attackers to cause a denial of service (NULL pointer dereference and application crash) and possibly have unspecified other impact via a crafted argument.
http://www.vupen.com/english/advisories/2010/3081
http://www.vupen.com/english/advisories/2010/0724
http://www.redhat.com/support/errata/RHSA-2010-0919.html
http://www.mandriva.com/security/advisories?name=MDVSA-2010:068
http://support.apple.com/kb/HT4435
http://support.apple.com/kb/HT4312
http://secunia.com/advisories/42410
http://lists.opensuse.org/opensuse-security-announce/2010-09/msg00006.html
http://lists.opensuse.org/opensuse-security-announce/2010-06/msg00001.html
http://lists.opensuse.org/opensuse-security-announce/2010-05/msg00002.html
http://lists.apple.com/archives/security-announce/2010//Nov/msg00000.html
http://lists.apple.com/archives/security-announce/2010//Aug/msg00003.html