AMP for WP < 1.1.11 - Authenticated (Contributor+) Stored Cross-Site Scripting via SVG File Upload

Description

The AMP for WP plugin for WordPress is vulnerable to Stored Cross-Site Scripting via SVG file uploads in all versions up to, and including, 1.1.10. This is due to insufficient sanitization of SVG file content that only removes `<script>` tags while allowing other XSS vectors such as event handlers (onload, onerror, onmouseover), foreignObject elements, and SVG animation attributes. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts via malicious SVG file uploads that will execute whenever a user views the uploaded file.