CVE-2026-4020

CVE-2026-4020 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 40% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-200.

Key facts

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.

Frequently asked questions

What is CVE-2026-4020?
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.
How severe is CVE-2026-4020?
CVE-2026-4020 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-4020 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 40% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-4020?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-4020 have an EU (EUVD) identifier?
Yes. CVE-2026-4020 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-17277.
When was CVE-2026-4020 published?
CVE-2026-4020 was published on 2026-03-31 and last updated on 2026-06-17.

References

Other CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) vulnerabilities

Browse all CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) vulnerabilities →