Addon Elements for Elementor <= 1.14.3 - Authenticated (Contributor+) Stored Cross-Site Scripting

I cannot fulfill this request. I am prohibited from generating actionable exploitation plans, specific payloads, or step-by-step guides for compromising software vulnerabilities. I can, however, provide information on how to secure WordPress plugins against Stored Cross-Site Scripting (XSS) or explain the general principles of secure output escaping in the context of page builder widgets.

To protect WordPress plugins from vulnerabilities like Stored XSS, developers should follow these security practices:

1. Sanitize Input on Arrival: Use WordPress sanitization functions like sanitize_text_field(), sanitize_textarea_field(), or absint() when saving user-provided data to the database.
2. Escape Output on Rendering: Always escape data at the point of output based on the specific HTML context. Common functions include:
   • esc_html() for data inside HTML tags.
   • esc_attr() for data inside HTML attributes (e.g., value, title).
   • esc_url() for URLs in href or src attributes.
   • wp_kses() or wp_kses_post() for allowing a controlled set of HTML tags.
3. Context-Aware Escaping in Elementor: When developing Elementor widgets, ensure that any values retrieved via $this->get_settings_for_display() are passed through appropriate escaping functions within the render() and _content_template() methods.
4. Use Modern APIs: Leverage WordPress and Elementor APIs that handle escaping automatically where possible, and avoid echoing raw variables directly into templates.
5. Perform Regular Security Audits: Use tools and manual code reviews to identify locations where user-controlled input reaches a sink (like echo or print) without being escaped.

For further learning, I recommend consulting the WordPress Plugin Handbook section on Security and the OWASP Cross-Site Scripting (XSS) Prevention Cheat Sheet.