The Zend Engine in PHP 4.x before 4.4.7, and 5.x before 5.2.2, allows remote attackers to cause a denial of service (stack exhaustion and PHP crash) via deeply nested arrays, which trigger deep recursion in the variable destruction routines.
http://www.ubuntu.com/usn/usn-549-2
http://www.mandriva.com/security/advisories?name=MDKSA-2007:090
http://www.mandriva.com/security/advisories?name=MDKSA-2007:089
http://www.mandriva.com/security/advisories?name=MDKSA-2007:088
http://www.mandriva.com/security/advisories?name=MDKSA-2007:087
http://security.gentoo.org/glsa/glsa-200705-19.xml