CVE-2025-64367: Groundhogg WordPress Plugin XSS Vulnerability

CVE-2025-64367 Overview

CVE-2025-64367 is a stored cross-site scripting (XSS) vulnerability in the Groundhogg WordPress plugin developed by Adrian Tobey. The flaw stems from improper neutralization of user-supplied input during web page generation, classified under [CWE-79]. Attackers with low-privileged authenticated access can inject malicious scripts that persist in the application and execute in the browsers of other users. The vulnerability affects all Groundhogg versions up to and including 4.2.6. Successful exploitation requires user interaction and can lead to session compromise, credential theft, and unauthorized actions performed in the context of privileged WordPress accounts.

Critical Impact
Authenticated attackers can inject persistent JavaScript payloads that execute against WordPress administrators, enabling account takeover and site compromise through the Groundhogg plugin.

Affected Products

Adrian Tobey Groundhogg plugin for WordPress
All versions from initial release through 4.2.6
WordPress sites running the Groundhogg CRM and marketing automation plugin

Discovery Timeline

2025-10-31 - CVE-2025-64367 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in the NVD database

Technical Details for CVE-2025-64367

Vulnerability Analysis

The vulnerability is a stored XSS flaw in the Groundhogg plugin, a customer relationship management (CRM) and marketing automation tool for WordPress. Groundhogg fails to properly sanitize or encode user-controlled input before rendering it in web pages served to other users. As a result, an attacker with authenticated access can submit crafted input containing HTML or JavaScript that is stored in the plugin's data and later reflected without adequate encoding.

When a victim, typically an administrator or another authenticated user, views the affected page, the injected script executes within the victim's browser session. Because the payload runs in the context of the WordPress origin, it can steal session cookies, forge administrative requests, modify plugin data, or pivot to further compromise of the WordPress installation.

The scope-changed nature of the flaw indicates the injected script can affect resources outside the initial security boundary, consistent with typical stored XSS in WordPress administrative interfaces. See the Patchstack advisory for additional technical context.

Root Cause

The root cause is missing or insufficient output encoding when user-supplied data is rendered by the Groundhogg plugin. Input accepted from authenticated users is stored and later included in generated HTML without contextual escaping, allowing script tags and event handler attributes to be interpreted by the browser.

Attack Vector

Exploitation requires network access, low privileges on the target WordPress site, and user interaction from a victim. An attacker authenticates with a low-privileged account, submits a payload through an input field processed by Groundhogg, and waits for a higher-privileged user to view the affected view. The victim's browser then executes the attacker's JavaScript in the site's origin.

No public proof-of-concept exploit code has been verified for this issue. See the Patchstack advisory for reference.

Detection Methods for CVE-2025-64367

Indicators of Compromise

Unexpected <script> tags, javascript: URIs, or event handler attributes (onerror, onload, onmouseover) stored in Groundhogg contact, tag, or form-related database tables.
WordPress administrative sessions initiating unusual outbound requests to attacker-controlled domains shortly after viewing Groundhogg pages.
Creation of new WordPress administrator accounts or unexpected changes to user roles following administrator access to Groundhogg views.

Detection Strategies

Audit Groundhogg-related database entries for HTML markup and JavaScript payload patterns in fields that should contain plain text.
Deploy a web application firewall (WAF) rule set targeting stored XSS patterns for /wp-admin/ requests handling Groundhogg endpoints.
Review WordPress access logs for POST requests to Groundhogg endpoints from low-privileged users containing suspicious characters such as <, >, or encoded script fragments.

Monitoring Recommendations

Enable a strict Content Security Policy (CSP) in report-only mode to surface unexpected inline script execution on WordPress admin pages.
Monitor WordPress user activity logs for privilege changes, plugin modifications, or option updates performed by administrators shortly after loading Groundhogg views.
Alert on new or modified Groundhogg records that contain HTML tags in fields expected to hold text-only values.

How to Mitigate CVE-2025-64367

Immediate Actions Required

Update the Groundhogg plugin to a version later than 4.2.6 as soon as a patched release becomes available from the vendor.
Restrict Groundhogg access to trusted users and audit existing low-privileged accounts that can submit input to the plugin.
Review stored Groundhogg data for previously injected payloads and sanitize or remove any suspicious entries.

Patch Information

The vulnerability affects Groundhogg versions up to and including 4.2.6. Administrators should consult the Patchstack advisory and the plugin's official channels for the fixed version and apply the update across all affected WordPress installations.

Workarounds

Temporarily disable the Groundhogg plugin on production WordPress instances if a patched version is not yet installed.
Enforce a Content Security Policy that disallows inline scripts and restricts script sources to trusted origins.
Limit administrative access to Groundhogg pages by role and require multi-factor authentication (MFA) for all WordPress accounts with plugin management privileges.

bash

# Update Groundhogg via WP-CLI once a fixed version is released
wp plugin update groundhogg

# Verify installed version
wp plugin get groundhogg --field=version

# Temporarily deactivate the plugin if patching is delayed
wp plugin deactivate groundhogg