Language: PHP
Label: safe
CWE: CWE-79 \u2014 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Code:
    protected function forwardUntilEndToken(&$i, &$current, &$nesting)
    {
        $result = $this->forward($i, $current);
        if (!$result) {
            return false;
        }
        if ($nesting === null) {
            $nesting = 0;
        }
        if ($current instanceof HTMLPurifier_Token_Start) {
            $nesting++;
        } elseif ($current instanceof HTMLPurifier_Token_End) {
            if ($nesting <= 0) {
                return false;
            }
            $nesting--;
        }
        return true;
    }