GetSimple CMS Cross-Site Scripting Vulnerability

GetSimple CMS is a content management system (CMS) written in PHP. A cross-site scripting vulnerability exists in GetSimple CMS version 3.3.16, which stems from the lack of effective filtering and escaping of user-supplied data when adding articles to the /admin/edit.php page, and can be exploited by an attacker to execute arbitrary Web script or HTML by injecting a carefully crafted payload.