Oracle MySQL 5.1 before 5.1.49 allows remote authenticated users to cause a denial of service (crash) via (1) IN or (2) CASE operations with NULL arguments that are explicitly specified or indirectly provided by the WITH ROLLUP modifier.
http://www.vupen.com/english/advisories/2011/0170
http://www.vupen.com/english/advisories/2011/0133
http://www.ubuntu.com/usn/USN-1397-1
http://www.ubuntu.com/usn/USN-1017-1
http://www.securityfocus.com/bid/42596
http://www.redhat.com/support/errata/RHSA-2011-0164.html
http://www.mandriva.com/security/advisories?name=MDVSA-2011:012
http://www.mandriva.com/security/advisories?name=MDVSA-2010:155
http://secunia.com/advisories/42936
http://lists.opensuse.org/opensuse-security-announce/2010-10/msg00006.html