includes/functions.php in Craig Knudsen WebCalendar before 1.0.5 does not protect the noSet variable from external modification, which allows remote attackers to set arbitrary global variables via a URL with modified values in the noSet parameter, which leads to resultant vulnerabilities that probably include remote file inclusion and other issues.
Cross-site scripting (XSS) vulnerability in export_handler.php in WebCalendar 1.0.4 and earlier allows remote attackers to inject arbitrary web script or HTML via the format parameter.