CVE-2026-40793: Groundhogg Auth Bypass Vulnerability

CVE-2026-40793 Overview

CVE-2026-40793 is a broken access control vulnerability affecting the Groundhogg WordPress plugin in versions prior to 4.4.1. The flaw stems from missing authorization checks [CWE-862] in plugin functionality accessible to authenticated users at the Subscriber role. An attacker holding low-privilege Subscriber credentials can invoke restricted actions over the network without additional user interaction. The issue affects data integrity on WordPress sites running vulnerable Groundhogg versions while leaving confidentiality and availability unaffected based on the published CVSS vector.

Critical Impact
Authenticated Subscriber-level users can perform actions reserved for higher-privileged accounts, enabling integrity-impacting modifications to Groundhogg-managed CRM and marketing automation data.

Affected Products

Groundhogg WordPress plugin versions prior to 4.4.1
WordPress sites with Subscriber registration enabled running vulnerable Groundhogg builds
Groundhogg CRM and marketing automation deployments using affected releases

Discovery Timeline

2026-06-15 - CVE-2026-40793 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2026-40793

Vulnerability Analysis

The vulnerability is a Broken Access Control issue classified under [CWE-862] Missing Authorization. Groundhogg exposes plugin endpoints that fail to verify the caller's capability before executing sensitive actions. Any authenticated user, including the default WordPress Subscriber role, can reach these endpoints over the network.

The published CVSS vector indicates the attack requires network access and low privileges, with no user interaction. Impact is concentrated on integrity, meaning attackers can modify Groundhogg-managed records but cannot directly read protected data or take the site offline through this flaw.

Given Groundhogg's role as a CRM and marketing automation plugin, integrity impact extends to contact records, tags, funnels, and related automation objects. Tampering with these structures can poison downstream email campaigns and contact segmentation logic.

Root Cause

The root cause is the absence of capability checks such as current_user_can() or nonce validation paired with role enforcement on plugin handlers. Endpoints intended for administrators or marketing managers accept requests from any authenticated session, including Subscriber accounts created through open WordPress registration.

Attack Vector

An attacker registers or obtains a Subscriber account on the target WordPress site. The attacker then sends crafted requests to the vulnerable Groundhogg endpoints, invoking actions that the plugin should restrict to privileged roles. The exploitation path requires no social engineering and no chained vulnerability. The vulnerability mechanism is described in the Patchstack Groundhogg Plugin Vulnerability advisory.

Detection Methods for CVE-2026-40793

Indicators of Compromise

Unexpected modifications to Groundhogg contacts, tags, funnels, or broadcast configurations attributable to Subscriber-role accounts
WordPress audit log entries showing Subscriber users invoking admin-ajax.php or REST routes scoped to Groundhogg administration
New Subscriber registrations followed shortly by anomalous POST requests to Groundhogg plugin endpoints

Detection Strategies

Inspect web server access logs for authenticated requests to Groundhogg endpoints originating from non-administrative session cookies
Correlate WordPress user role with the privileges required by each invoked plugin action and alert on mismatches
Deploy a WordPress activity logging plugin to capture Groundhogg object changes with the originating user role recorded

Monitoring Recommendations

Track the installed Groundhogg version across managed WordPress sites and alert on builds below 4.4.1
Monitor for spikes in Subscriber account creation followed by Groundhogg API activity
Forward WordPress and web server logs to a centralized analytics platform for cross-site pattern detection

How to Mitigate CVE-2026-40793

Immediate Actions Required

Upgrade Groundhogg to version 4.4.1 or later on every WordPress instance where the plugin is installed
Audit existing Subscriber accounts and remove any that cannot be attributed to legitimate users
Review Groundhogg contact, tag, and funnel data for unauthorized modifications dating back to plugin installation

Patch Information

Groundhogg version 4.4.1 remediates the missing authorization checks. Site operators should apply the update through the WordPress plugin manager or WP-CLI. Refer to the Patchstack advisory for vendor patch details.

Workarounds

Disable open user registration in WordPress settings until the plugin is patched to remove the trivial path to Subscriber credentials
Restrict access to /wp-admin/admin-ajax.php and Groundhogg REST routes at the web application firewall for non-administrative roles
Temporarily deactivate the Groundhogg plugin on sites that cannot be updated immediately

bash

# Update Groundhogg via WP-CLI to the patched release
wp plugin update groundhogg --version=4.4.1

# Verify the installed version after update
wp plugin get groundhogg --field=version

# Disable open registration as a temporary hardening step
wp option update users_can_register 0