CVE-2026-39655: Mayosis Core Authorization Bypass Flaw

CVE-2026-39655 Overview

CVE-2026-39655 is a Missing Authorization vulnerability [CWE-862] affecting the TeconceTheme Mayosis Core plugin for WordPress. The flaw exists in all versions up to and including 5.4.7. The plugin fails to enforce proper access control checks on certain functionality, allowing unauthenticated network attackers to access actions or resources intended for authorized users. Exploitation requires no privileges and no user interaction, and the attack vector is the network.

Critical Impact
Unauthenticated attackers can exploit incorrectly configured access control security levels in Mayosis Core to perform actions that should require authorization, resulting in limited integrity impact on affected WordPress sites.

Affected Products

TeconceTheme Mayosis Core (WordPress plugin)
All versions from initial release through 5.4.7
WordPress sites using the Mayosis digital marketplace theme stack

Discovery Timeline

2026-05-26 - CVE CVE-2026-39655 published to NVD
2026-05-26 - Last updated in NVD database

Technical Details for CVE-2026-39655

Vulnerability Analysis

The vulnerability stems from missing authorization checks in the Mayosis Core plugin. The plugin exposes functionality that should be gated by capability or role verification but instead relies on incorrectly configured access control logic. An unauthenticated attacker can issue HTTP requests to reach these endpoints directly. The attack complexity is low and no user interaction is needed. The impact is limited to integrity, with no direct disclosure of confidential data or denial of service noted in the advisory.

Missing Authorization (CWE-862) issues in WordPress plugins typically occur when handlers registered through admin-post.php, admin-ajax.php, or REST API routes omit calls to current_user_can() or fail to validate the user's role before executing privileged logic. The result is that an action intended for site administrators or authenticated subscribers can be triggered by any visitor.

Root Cause

The root cause is improperly configured access control on plugin functionality in Mayosis Core through version 5.4.7. The handlers either omit capability checks entirely or apply checks that do not reflect the intended security level for the affected action.

Attack Vector

An attacker sends crafted HTTP requests to a vulnerable WordPress site exposing the Mayosis Core plugin. Because the affected endpoint does not validate the caller's authorization, the request executes server-side logic that should be restricted. Refer to the Patchstack WordPress Vulnerability advisory for technical details on the affected handler.

Detection Methods for CVE-2026-39655

Indicators of Compromise

Unexpected HTTP POST or GET requests to Mayosis Core plugin endpoints under /wp-admin/admin-ajax.php or /wp-json/ originating from unauthenticated sessions.
Modifications to plugin-managed records, settings, or marketplace items without a corresponding administrator login event in WordPress audit logs.
Requests targeting Mayosis Core action names that arrive without valid nonce parameters or session cookies.

Detection Strategies

Enable verbose access logging on the web server and alert on repeated requests to Mayosis Core action handlers from a single IP without authentication cookies.
Deploy a WordPress security plugin or Web Application Firewall (WAF) rule set that flags requests matching the Patchstack signature for this advisory.
Correlate WordPress wp_options and post metadata changes with the originating HTTP request to identify unauthorized state changes.

Monitoring Recommendations

Monitor the installed version of Mayosis Core across all WordPress instances and alert when the version is at or below 5.4.7.
Track outbound integrity changes (post creation, option updates) generated by the plugin and validate them against expected administrator activity.
Forward WordPress and web server logs to a centralized log platform for retention and search during incident response.

How to Mitigate CVE-2026-39655

Immediate Actions Required

Inventory all WordPress sites using TeconceTheme Mayosis Core and identify any running version 5.4.7 or earlier.
Update Mayosis Core to a version above 5.4.7 once the vendor publishes a patched release.
Restrict access to /wp-admin/admin-ajax.php and /wp-json/ endpoints associated with Mayosis Core using WAF rules until patching is complete.

Patch Information

At publication, the advisory lists affected versions from initial release through 5.4.7. Site operators should consult the Patchstack WordPress Vulnerability advisory for the current fixed version and apply the update through the WordPress plugin management interface or by replacing the plugin files on disk.

Workarounds

Apply virtual patching at the WAF layer to block unauthenticated requests to the vulnerable Mayosis Core endpoints.
Temporarily deactivate the Mayosis Core plugin if the affected functionality is not business-critical.
Enforce IP allow-listing on the WordPress administration interface to reduce the exposure surface.

bash

# Configuration example: block unauthenticated access to Mayosis Core AJAX actions at the Nginx layer
location = /wp-admin/admin-ajax.php {
    if ($arg_action ~* "^mayosis_") {
        if ($http_cookie !~* "wordpress_logged_in_") {
            return 403;
        }
    }
    include fastcgi_params;
    fastcgi_pass php_upstream;
}