Smarty before 3.1.21 allows remote attackers to bypass the secure mode restrictions and execute arbitrary PHP code as demonstrated by "{literal}<{/literal}script language=php>" in a template.
Cross-site scripting (XSS) vulnerability in the SmartyException class in Smarty (aka smarty-php) before 3.1.12 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors that trigger a Smarty exception.