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:
    public function __construct($non_negative = false)
    {
        $this->number_def = new HTMLPurifier_AttrDef_CSS_Number($non_negative);
    }