The Zend Engine in PHP 4.x before 4.4.7, and 5.x before 5.2.2, allows remote attackers to cause a denial of service (stack exhaustion and PHP crash) via deeply nested arrays, which trigger deep recursion in the variable destruction routines.
Stack-based buffer overflow in the sslutiluuencodebinary function in sslutil.c for Apache modssl, when modssl is configured to trust the issuing CA, may allow remote attackers to execute arbitrary code via a client certificate with a long subject DN.