CVE-2026-4020
HIGH · 7.5 EPSS 3.0%Real vuln, active attacker chatter, no KEV yet; unclear scale of exploitation.
What: Gravity SMTP WordPress plugin (≤2.1.4) exposes 365 KB of sensitive system data via unauthenticated REST API endpoint—CVSS 7.5 HIGH.
Why it matters: Real vulnerability with clear attack surface (no auth required, REST endpoint discoverable). Posts reference active reconnaissance ("attackers are the same client"), suggesting in-the-wild targeting. No KEV listing yet, but EPSS low (0.03) and chatter is recent (June 2026). CrowdSec advisory noted; defenders likely triaging WordPress instances.
Where it's seen: French-language security media, HackerNews discussion threads, blog coverage from honeylabs and cyberveille flagging live reconnaissance activity and shared attacker infrastructure.
RISK: HIGH — Unauthenticated info disclosure leaks API keys, plugin roster, DB details; active scanning observed.
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.
CVSS 3.1 breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N- Attack vector
- Network
- Complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Weaknesses
References
- https://docs.gravitysmtp.com/gravity-smtp-changelog/
- https://plugins.trac.wordpress.org/browser/gravitysmtp/tags/2.1.4/vendor/gravityforms/gravity-tools/src/Providers/class-config-collection-service-provider.php#L103
- https://plugins.trac.wordpress.org/browser/gravitysmtp/tags/2.1.4/vendor/gravityforms/gravity-tools/src/Providers/class-config-collection-service-provider.php#L86
- https://plugins.trac.wordpress.org/browser/gravitysmtp/trunk/vendor/gravityforms/gravity-tools/src/Providers/class-config-collection-service-provider.php#L103
- https://plugins.trac.wordpress.org/browser/gravitysmtp/trunk/vendor/gravityforms/gravity-tools/src/Providers/class-config-collection-service-provider.php#L86
- https://www.gravityforms.com/gravity-smtp/
- https://www.wordfence.com/threat-intel/vulnerabilities/id/12a296db-ecc0-409b-8718-0c208504053a?source=cve