Zend/zend_hash.c in PHP before 7.0.15 and 7.1.x before 7.1.1 mishandles certain cases that require large array allocations, which allows remote attackers to execute arbitrary code or cause a denial of service (integer overflow, uninitialized memory access, and use of arbitrary destructor function pointers) via crafted serialized data.
https://security.netapp.com/advisory/ntap-20180112-0001/
https://github.com/php/php-src/commit/4cc0286f2f3780abc6084bcdae5dce595daa3c12
https://bugs.php.net/bug.php?id=73832
https://access.redhat.com/errata/RHSA-2018:1296