ExtCalendar is a powerful multi-user web-based calendar application. Features include Multi-Languages, Themes, Recurrent Events, Categories, Users and Groups management, Environment and General Settings, Template Configuration, Product Updates.
ExtCalendar is prone to a cross-site scripting vulnerability because it fails to properly sanitize user-supplied input. An attacker may leverage this issue to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site. This may allow the attacker to steal cookie-based authentication credentials and to launch other attacks. The issue exist in the upgrade.php script in the html_footer() function, line 361. Conditional on register_globals turned ON. This vuln was found using Pixy code auditor.