The sanitize_string function in ZenPhoto before 1.4.9 utilized the html_entity_decode function after input sanitation, which might allow remote attackers to perform a cross-site scripting (XSS) via a crafted string.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2015-5548
http://www.zenphoto.org/news/zenphoto-1.4.9