Frontend Post Submission Manager Lite <= 1.3.4 - Unauthenticated Stored DOM-Based Cross-Site Scripting via post_content Parameter (data-label DOM Sink)

The Frontend Post Submission Manager Lite – Frontend Posting WordPress Plugin plugin for WordPress is vulnerable to Stored DOM-Based Cross-Site Scripting via post_content Parameter (data-label DOM Sink) in all versions up to, and including, 1.3.4 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires the site operator to have enabled guest post submission via the [fpsm] shortcode, which registers a publicly accessible AJAX handler gated only by a nonce emitted on every page containing the shortcode.