The MailPoet plugin for the WordPress blogging platform has been found to be vulnerable to an exploit that allows a potential attacker to upload any file to the affected website, without having to provide any authentication credentials.The plugin has been downloaded more than 1.7 million times, and its popularity is owed to the fact that it facilitates the sending of newsletters to subscribers, post notifications and auto-responders from WordPress-powered websites.Daniel Cid, CTO of security c…