Input validation vulnerability in Multi Step Form 1.7.11

The Multi Step Form plugin for WordPress has a security vulnerability in all versions up to version 1.7.11. This vulnerability makes it possible for unauthenticated attackers to perform malicious actions such as duplicating, editing, and deleting forms. This is possible if the attackers can convince a site administrator to click on a malicious link. To fix this issue, the plugin developers need to add nonce validation to the menu() function.