CVE-2026-18146: Fluent Forms <= 6.2.11 - Unauthenticated Stored Cross-Site Scripting via Notification Smartcode Values

The Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Notification Smartcode Values in all versions up to, and including, 6.2.11 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts that execute in the browser of an administrator (or any user with the Fluent Forms entry-viewing capability) when they view the form's entry Submission Logs in the WordPress admin dashboard. Exploitation requires that a site administrator or Fluent Forms manager has configured an email notification whose subject or static (direct) Send To value references an attacker-influenced Smartcode such as an inputpassword field value, a cookie value, or submission.response.