WordPress users with the Advanced Custom Fields plugin on their website should upgrade after the discovery of a vulnerability in the code that could open up sites and their visitors to cross-site scripting (XSS) attacks. Essentially, it allows someone to run JavaScript within another person's view of a page, allowing the attacker to do things like steal information from the page, perform actions as the user, and so on. That's a big problem if the visitor is a logged-in administrative user, as their account could be hijacked to take over the website.
https://www.theregister.com/2023/05/08/wordpress_plugin_vulnerability/?td=rt-3a