The WP ULike plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `[wp_ulike_likers_box]` shortcode `template` attribute in all versions up to, and including, 5.0.1. This is due to the use of `html_entity_decode()` on shortcode attributes without subsequent output sanitization, which effectively bypasses WordPress's `wp_kses_post()` content filtering. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The post must have at least one like for the XSS to render.
