CVE 2011-3182
PHP before 5.3.7 does not properly check the return values of the malloc, calloc, and realloc library functions, which allows context-dependent attackers to cause a denial of service (NULL pointer dereference and application crash) or trigger a buffer overflow by leveraging the ability to provide an arbitrary value for a function argument, related to (1) ext/curl/
See the
CVE page on Mitre.org
for more details.