The UsersWP – Front-end login form, User Registration, User Profile & Members Directory plugin for WordPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's shortcode(s) in all versions up to, and including, 1.2.6 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers with contributor-level and above permissions to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as "<", ">", and "&" that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages.