Gravity SMTP - Information Disclosure (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.
psychologyCrowdSec Analysis
CVE-2026-4020 is an information disclosure vulnerability in the Gravity SMTP plugin for WordPress, affecting all versions up to and including 2.1.4. Due to improper REST API permissions, unauthenticated attackers can access a system report containing sensitive configuration data such as PHP and web server versions, database details, active plugins, themes, and even API keys or tokens. This exposure significantly increases the risk of targeted attacks, reconnaissance, and further exploitation of the affected WordPress site.
CrowdSec has been tracking this vulnerability and its exploits since 22nd of May 2026.
CrowdSec network data shows that most actors exploiting CVE-2026-4020 rely on broad, untargeted scans with minimal filtering. The activity is largely automated and opportunistic in nature. Telemetry from the CrowdSec network also shows that exploitation activity for CVE-2026-4020 remains steady week-over-week. Attack volumes are consistent with long-term trends, indicating sustained interest from threat actors. CVE-2026-4020 continues to be an active part of the threat landscape and will likely remain this way for the forseeable future.
Attackers exploit the unrestricted REST API endpoint /wp-json/gravitysmtp/v1/tests/mock-data to retrieve sensitive system configuration data from vulnerable WordPress sites running the Gravity SMTP plugin. This endpoint is targeted with unauthenticated GET requests, exposing detailed information that could facilitate further attacks.
Full Intelligence Available
Connect your API key to access CrowdSec scores, exploit timelines, and attacker IPs.
| Event | Date |
|---|---|
| CVE Published | 2026-03-31 |
| Rule Released | 2026-05-22 |
| CrowdSec First Seen | 2026-05-27 |