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

Q: What is CVE-2026-4020?

CVE-2026-4020 is a high-severity vulnerability in RocketGenius Gravity SMTP, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Q: Is CVE-2026-4020 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4020 exists.

Q: How do I fix CVE-2026-4020?

No fix has been published for CVE-2026-4020 yet. Limit exposure of the affected software until one is available.

High 7.5 Published 31 Mar 2026 Updated 8 Apr 2026

Unauthenticated attackers can access a REST API endpoint to retrieve sensitive system configuration data and API keys from the Gravity SMTP plugin.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-4020?

CVE-2026-4020 is a high-severity vulnerability in RocketGenius Gravity SMTP, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-200

Which versions are affected by CVE-2026-4020?

How do I fix CVE-2026-4020?

No fix has been published for CVE-2026-4020 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-4020 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4020 exists.

Public exploit code: 1 Nuclei template and 2 proofs of concept on GitHub.

Sources

Also known as GHSA-jxfc-8wcq-xxcg.