CVE-2026-39594 Overview
CVE-2026-39594 is a broken access control vulnerability in the Ultra Addons for WPForms WordPress plugin affecting versions up to and including 1.0.11. The flaw stems from missing authorization checks [CWE-862], allowing authenticated users with low-privilege Subscriber accounts to perform actions reserved for higher-privileged roles. An attacker exploits this issue over the network with low complexity and no user interaction. The scope changes when triggered, meaning the impact extends beyond the vulnerable component itself. Patchstack disclosed the vulnerability and assigned it medium severity due to limited integrity and availability impact.
Critical Impact
Authenticated Subscriber-level users can bypass authorization controls in Ultra Addons for WPForms <= 1.0.11, leading to unauthorized modification of plugin data and limited service disruption on affected WordPress sites.
Affected Products
- Ultra Addons for WPForms plugin for WordPress
- Versions 1.0.11 and earlier
- WordPress sites with the plugin installed and active
Discovery Timeline
- 2026-06-15 - CVE-2026-39594 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2026-39594
Vulnerability Analysis
The vulnerability is a Broken Access Control issue classified under [CWE-862] Missing Authorization. The plugin exposes one or more actions, endpoints, or AJAX handlers without verifying that the requesting user holds the appropriate WordPress capability. Any authenticated user, including the default Subscriber role, can invoke these handlers and perform privileged operations. The scope-changing nature of the flaw indicates that exploitation affects resources beyond the plugin's own security boundary, such as form configuration or site-level settings. The Exploit Prediction Scoring System currently rates exploitation likelihood as low, and no public proof-of-concept is published at this time.
Root Cause
The root cause is the absence of current_user_can() capability checks and missing nonce verification on plugin endpoints in Ultra Addons for WPForms <= 1.0.11. The plugin relies on the user being authenticated without enforcing role-based authorization. WordPress sites that permit open registration grant Subscriber accounts to anonymous visitors by default, lowering the barrier to exploitation.
Attack Vector
An attacker first obtains a Subscriber-level account on the target WordPress site through self-registration or credential reuse. The attacker then sends crafted HTTP requests to the vulnerable plugin endpoints, invoking actions that should require Editor or Administrator capabilities. The vulnerability manifests in plugin handlers that omit authorization gating. Refer to the Patchstack Vulnerability Report for advisory details.
Detection Methods for CVE-2026-39594
Indicators of Compromise
- Unexpected POST requests from Subscriber-level users to admin-ajax.php referencing Ultra Addons for WPForms actions.
- Modifications to WPForms configurations or form submissions performed by accounts without Editor or Administrator roles.
- Newly registered Subscriber accounts followed by anomalous plugin-related API traffic.
Detection Strategies
- Audit WordPress access logs for requests to plugin endpoints originating from low-privilege user sessions.
- Compare WPForms and plugin option changes against the WordPress user role responsible for the change.
- Apply web application firewall rules that inspect plugin action parameters and validate the calling user's role.
Monitoring Recommendations
- Monitor the wp_users and wp_usermeta tables for unexpected role changes or privilege escalations.
- Track creation rates of Subscriber accounts and correlate with plugin endpoint activity.
- Alert on changes to WPForms form definitions performed outside maintenance windows.
How to Mitigate CVE-2026-39594
Immediate Actions Required
- Update Ultra Addons for WPForms to a version later than 1.0.11 once the vendor releases a patched build.
- Disable open user registration on WordPress sites that do not require it by unchecking Settings > General > Membership.
- Audit existing Subscriber accounts and remove unrecognized users.
Patch Information
No fixed version is referenced in the available CVE record beyond noting that 1.0.11 and earlier are affected. Administrators should consult the Patchstack Vulnerability Report and the plugin's WordPress.org page for patched release availability.
Workarounds
- Deactivate and remove Ultra Addons for WPForms until a patched version is installed.
- Restrict access to wp-admin/admin-ajax.php and REST API plugin routes using a WAF or server-level access rules.
- Enforce the principle of least privilege by reviewing role assignments and disabling unused capabilities for Subscriber accounts.
# Configuration example: disable open registration via wp-cli
wp option update users_can_register 0
# List active plugins and identify the vulnerable component
wp plugin list --status=active --format=table | grep ultra-addons-for-wpforms
# Deactivate the plugin until a patched version is available
wp plugin deactivate ultra-addons-for-wpforms
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
