Integer overflow in the 16 bit variable reference counter in PHP 4 allows context-dependent attackers to execute arbitrary code by overflowing this counter, which causes the same variable to be destroyed twice, a related issue to CVE-2007-1286.

Integer overflow in PHP 4.4.4 and earlier allows remote context-dependent attackers to execute arbitrary code via a long string to the unserialize function, which triggers the overflow in the ZVAL reference counter.