The Essential Addons for Elementor plugin, which is used to create templates, widgets, and other elements on WordPress websites, has a security vulnerability. This means that hackers can insert malicious code into pages that will run whenever someone visits that page. The vulnerability affects all versions up to 5.9.8 and is caused by a lack of proper protection against harmful input and output. This could potentially be exploited by attackers who have contributor-level access or higher.