Glossarizer through 1.5.2 improperly tries to convert text into HTML. Even though the application itself escapes special characters (e.g., <>), the underlying library converts these encoded characters into legitimate HTML, thereby possibly causing stored XSS. Attackers can append a XSS payload to a word that has a corresponding glossary entry.
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.