Input validation vulnerability in My Calendar 2.5.17

The My Calendar plugin for WordPress is not secure in versions up to and including 2.6.16. Attackers who have permission to make changes to the website can inject malicious code into the website, which will run when someone visits the page. This code can do things like steal information from the user’s computer or take control of their account. To protect your website, it is important to update to a more secure version of the My Calendar plugin.