CVE 2014-3515
The SPL component in PHP before 5.4.30 and 5.5.x before 5.5.14 incorrectly anticipates that certain data structures will have the array data type after unserialization, which allows remote attackers to execute arbitrary code via a crafted string that triggers use of a Hashtable destructor, related to "type confusion" issues in (1) ArrayObject and (2) SPLObjectStorage.
See the 
CVE page on Mitre.org
for more details.
