validate.php in WebCalendar allows remote attackers to gain sensitive information via an invalid encoded_login parameter, which reveals the full path in an error message.
WebCalendar 0.9.34 and earlier with 'browsing in includes directory' enabled allows remote attackers to read arbitrary include files with .inc extensions from the web root.
WebCalendar 1.0.1 to 1.0.3 generates different error messages depending on whether or not a username is valid, which allows remote attackers to enumerate valid usernames.