PHP iCalendar 2.4 allows remote attackers to obtain sensitive information via a direct request to a .php file, which reveals the installation path in an error message, as demonstrated by rss/rss_common.php and certain other files.

Directory traversal vulnerability in print.php in PHP iCalendar 2.24 and earlier allows remote attackers to include and execute arbitrary local files via a .. (dot dot) in the cookie_language parameter in a phpicalendar_* cookie, a different vector than CVE-2006-1292.

admin/index.php in PHP iCalendar 2.3.4, 2.24, and earlier does not require administrative authentication for an addupdate action, which allows remote attackers to upload a calendar (aka .ics) file with arbitrary content to the calendars/ directory outside the web root.

PHP iCalendar 2.24 and earlier allows remote attackers to bypass authentication by setting the phpicalendar and phpicalendar_login cookies to 1.