Sanitize vulnerable to Improper Input Validation and Cross-site Scripting

When Sanitize <= 4.6.2 is used in combination with libxml2 >= 2.9.2, a specially crafted HTML fragment can cause libxml2 to generate improperly escaped output, allowing non-whitelisted attributes to be used on whitelisted elements.

This can allow HTML and JavaScript injection, which could result in XSS if Sanitize's output is served to browsers.