CVE-2026-4020 PoC — Gravity SMTP <= 2.1.4 - Unauthenticated Sensitive Information Exposure via REST API

Title:Gravity SMTP <= 2.1.4 - Unauthenticated Sensitive Information Exposure via REST API (CVE-2026-4020)
Description:The Gravity SMTP plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 2.1.4. This is due to a REST API endpoint registered at /wp-json/gravitysmtp/v1/tests/mock-data with a permission_callback that unconditionally returns true, allowing any unauthenticated visitor to access it. When the ?page=gravitysmtp-settings query parameter is appended, the plugin's register_connector_data() method populates internal connector data, causing the endpoint to return approximately 365 KB of JSON containing the full System Report. This makes it possible for unauthenticated attackers to retrieve detailed system configuration data including PHP version, loaded extensions, web server version, document root path, database server type and version, WordPress version, all active plugins with versions, active theme, WordPress configuration details, database table names, and any API keys/tokens configured in the plugin.

Gravity SMTP WordPress plugin <= 2.1.4 contains a sensitive information exposure caused by an unrestricted REST API endpoint at /wp-json/gravitysmtp/v1/tests/mock-data, letting unauthenticated attackers retrieve detailed system configuration data, exploit requires no authentication.

 id: CVE-2026-4020

info:
  name: Gravity SMTP WordPress Plugin - Sensitive Information Exposure
  au

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