The Schedule Post Changes With PublishPress Future plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'wrapper' attribute of the [futureaction] shortcode in all versions up to, and including, 4.10.0. This is due to insufficient input sanitization on the wrapper attribute. The plugin uses eschtml() to escape the value, but eschtml() only encodes HTML entities and does not prevent attribute injection when the value is used as an HTML tag name in a sprintf() call. An attacker can inject event handler attributes via spaces in the wrapper value. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Since it is also possible for administrators to make this functionality available to lower-privileged users, this introduces the possibility of abuse by contributors.