Smarty is a template engine for PHP. In affected versions smarty did not properly escape javascript code. An attacker could exploit this vulnerability to execute arbitrary JavaScript code in the context of the user's browser session. This may lead to unauthorized access to sensitive user data, manipulation of the web application's behavior, or unauthorized actions performed on behalf of the user. Users are advised to upgrade to either version 3.1.48 or to 4.3.1 to resolve this issue. There are no known workarounds for this vulnerability.

In Smarty before 3.1.47 and 4.x before 4.2.1, libs/plugins/function.mailto.php allows XSS. A web page that uses smarty_function_mailto, and that could be parameterized using GET or POST input parameters, could allow injection of JavaScript code by a user.