Cross-site scripting (XSS) vulnerability in plugins/calendar/calendar_backend.php in MyioSoft EasyCalendar 4.0tr and earlier allows remote attackers to inject arbitrary web script or HTML via the day parameter in a dayview action.
https://www.exploit-db.com/exploits/5246
https://exchange.xforce.ibmcloud.com/vulnerabilities/41180
http://www.securityfocus.com/archive/1/489678/100/0/threaded