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.
The record classifies CVE-2026-4020 under weakness class CWE-200. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 212 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 7.5 — HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - EPSS (FIRST)
- 2.2% probability of exploitation in the next 30 days, higher than 82.2% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 9.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-03-31, last modified 2026-04-08
Is CVE-2026-4020 being exploited?
Weaponised exploit code for CVE-2026-4020 is publicly available. 2 public proof-of-concept repositories are tracked for this identifier. A ProjectDiscovery Nuclei detection template exists (http/cves/2026/CVE-2026-4020.yaml). It currently carries a trending score of 36 in the Threadlinqs vulnerability feed.
- HORKimhab/CVE-2026-4020 (github)
- faizdotid/CVE-2026-4020 (github)
Affected products and versions
- RocketGenius: Gravity SMTP
How to fix CVE-2026-4020
No vendor patch reference has been recorded for CVE-2026-4020 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-4020
1 tracked threat in the Threadlinqs corpus references CVE-2026-4020, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories, ProjectDiscovery Nuclei. Last verified by Threadlinqs on .
Other references
- wordfence.com
- gravityforms.com
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org (class config collection service provider)
- plugins.trac.wordpress.org (class config collection service provider)
Showing 5 of 7 recorded references.