Input validation vulnerability in Subpage List 1.3.3

The Subpage List plugin used in WordPress has a security issue where attackers can insert harmful code into pages using the ‘subpages’ feature. This can happen in all versions up to 1.3.3 because the plugin does not properly clean and protect the information provided by users. This means that attackers with contributor-level access or higher can add their own code to a page, which will run whenever someone views that page.