Vk All In One Expansion Unit CVE-2026-39483

The vulnerability stems from improper input sanitization and output encoding in the VK All in One Expansion Unit plugin, a WordPress expansion toolkit that adds multiple features and page-building functionality. CWE-79 (Improper Neutralization of Input During Web Page Generation) indicates that user-supplied input is not properly escaped or filtered before being rendered in HTML context, allowing attackers to inject script tags or event handlers. The plugin processes user input through its various expansion features but fails to neutralize HTML metacharacters and JavaScript syntax, enabling stored payload persistence in the WordPress database. When an authenticated user (such as a contributor, editor, or author) submits malicious input via the plugin's input fields, that payload is stored unfiltered. Later, when administrators or other users view pages containing that content, the JavaScript executes in their browser context with their privileges.