php is vulnerable to arbitrary code execution. The vulnerability exists as a use-after-free flaw was found in the PHP substr_replace() function. If a PHP script used the same variable as multiple function arguments, a remote attacker could possibly use this to crash the PHP interpreter or, possibly, execute arbitrary code.
bugs.php.net/bug.php?id=54238
lists.apple.com/archives/security-announce/2012/Feb/msg00000.html
marc.info/?l=bugtraq&m=133469208622507&w=2
openwall.com/lists/oss-security/2011/03/13/2
openwall.com/lists/oss-security/2011/03/13/3
openwall.com/lists/oss-security/2011/03/13/9
support.apple.com/kb/HT5130
www.mandriva.com/security/advisories?name=MDVSA-2011:165
www.php.net/archive/2011.php#id2011-08-18-1
www.php.net/ChangeLog-5.php#5.3.7
www.php.net/security/crypt_blowfish.php
www.redhat.com/support/errata/RHSA-2011-1423.html
www.securityfocus.com/bid/46843
www.securityfocus.com/bid/49241
access.redhat.com/errata/RHSA-2011:1423
access.redhat.com/security/updates/classification/#moderate
exchange.xforce.ibmcloud.com/vulnerabilities/66080