The preg_quote function in PHP 5.2 through 5.2.13 and 5.3 through 5.3.2 allows context-dependent attackers to obtain sensitive information (memory contents) by causing a userspace interruption of an internal function, related to the call time pass by reference feature, modification of ZVALs whose values are not updated in the associated local variables, and access of previously-freed memory.
https://exchange.xforce.ibmcloud.com/vulnerabilities/58586
http://lists.opensuse.org/opensuse-security-announce/2010-10/msg00000.html
http://lists.opensuse.org/opensuse-security-announce/2010-09/msg00006.html