Notification for Telegram <= 3.5.1 - Missing Authorization to Authenticated (Subscriber+) Cron Modification via nftb_cron_action_set AJAX Action

I cannot fulfill the request to create a structured exploitation plan, actionable payloads, or step-by-step instructions for manipulating this plugin's functionality. Analyzing and developing functional exploit chains for specific vulnerabilities, including user-provided code, falls outside of my safety guidelines.

However, I can provide general information regarding the security principles involved and how developers can prevent similar authorization bypass issues in WordPress plugins.

Security Principles for WordPress AJAX Handlers

The vulnerability described (CVE-2026-7620) involves a "Missing Authorization" flaw in an AJAX action. In WordPress, security for AJAX endpoints typically relies on two primary mechanisms:

1. Authorization (Capability Checks):
   Plugins must verify that the user making the request has the necessary permissions to perform the action. This is done using the current_user_can() function.

   • The Flaw: When an AJAX action is registered using wp_ajax_action_name, any logged-in user (including those with the lowest "Subscriber" role) can trigger it. If the handler function does not check if the user is an administrator or has specific capabilities (like manage_options), a low-privileged user can execute high-privileged logic.
   • The Fix: Always verify capabilities at the start of the handler function.

     if ( ! current_user_can( 'manage_options' ) ) {
         wp_die( 'Unauthorized' );
     }
     

2. Authentication and CSRF Protection (Nonces):
   Nonces (Number used ONCE) in WordPress are used to ensure that a request was intentionally made by a specific user from a specific location (CSRF protection).

   • The Flaw: If a nonce is not generated on the settings page and then verified in the AJAX handler, an attacker could trick a logged-in administrator into performing actions or, in cases of missing authorization, a lower-privileged user could forge requests directly.
   • The Fix: Use wp_create_nonce() to generate a token and check_ajax_referer() or wp_verify_nonce() to validate it in the handler.

     check_ajax_referer( 'my_action_nonce', 'security' );
     

Understanding WordPress Cron Security

WordPress Cron (wp-cron.php) handles background tasks. Functions that modify the cron schedule, such as wp_schedule_event() or wp_unschedule_event(), are sensitive because they control when and how background processes run. Any user-facing interface that allows modification of these schedules must be strictly guarded by both capability checks and nonces to prevent unauthorized task manipulation or potential denial of service by rescheduling tasks excessively.

For more information on securing WordPress plugins, I recommend consulting the WordPress Plugin Handbook's Security Section and the OWASP Top 10 for general web security best practices.