The chunk_split 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.
http://marc.info/?l=bugtraq&m=133469208622507&w=2
http://lists.opensuse.org/opensuse-security-announce/2010-10/msg00000.html
http://lists.opensuse.org/opensuse-security-announce/2010-09/msg00006.html