CVE-2026-28567: WP Sort Order Auth Bypass Vulnerability

CVE-2026-28567 Overview

CVE-2026-28567 is a broken access control vulnerability in the WordPress plugin WP Sort Order affecting versions up to and including 1.3.5. The flaw allows unauthenticated attackers to reach plugin functionality that should be restricted to authorized users. The issue is categorized under CWE-862: Missing Authorization and is exposed over the network without requiring user interaction.

Critical Impact
Unauthenticated network-based attackers can invoke privileged plugin actions, resulting in confidentiality impact on affected WordPress sites running WP Sort Order<= 1.3.5.

Affected Products

WordPress plugin WP Sort Order versions <= 1.3.5
WordPress installations with the vulnerable plugin activated
Multi-site WordPress deployments where the plugin is network-enabled

Discovery Timeline

2026-08-18 - CVE-2026-28567 published to the National Vulnerability Database (NVD)
2026-08-20 - Last updated in NVD database

Technical Details for CVE-2026-28567

Vulnerability Analysis

The vulnerability stems from missing authorization checks on plugin endpoints exposed by WP Sort Order. An attacker can send crafted HTTP requests directly to plugin handlers without authenticating. The server processes those requests as if they came from a permitted user.

Because the plugin does not validate capability or nonce before executing sensitive actions, protected functionality becomes reachable by anonymous clients. The Patchstack advisory classifies the issue as broken access control impacting confidentiality on affected sites. Refer to the Patchstack WP Sort Order Vulnerability advisory for vendor-tracked details.

Root Cause

The root cause is a missing authorization control [CWE-862]. Plugin action handlers execute without calling WordPress capability functions such as current_user_can() and without verifying a request nonce through check_admin_referer() or wp_verify_nonce(). As a result, the plugin trusts request origin instead of verifying the requester.

Attack Vector

Exploitation occurs over the network against the WordPress HTTP interface. The attacker issues requests to admin-ajax.php or the plugin's registered endpoint with parameters that trigger the vulnerable action. No credentials, session, or user interaction are required. Successful exploitation exposes plugin-controlled data or state to the unauthenticated caller.

No public proof-of-concept code is available for CVE-2026-28567 at the time of publication. Technical details are described in prose only; see the Patchstack advisory for verified references.

Detection Methods for CVE-2026-28567

Indicators of Compromise

Unauthenticated POST or GET requests to admin-ajax.php referencing WP Sort Order action names
Unexpected changes to taxonomy, post, or menu ordering without a corresponding administrator session
Requests to plugin endpoints originating from IP addresses that have never authenticated to the site
Access log entries with anomalous User-Agent strings targeting /wp-admin/admin-ajax.php

Detection Strategies

Inspect web server access logs for requests to plugin AJAX actions arriving without a valid wordpress_logged_in cookie
Correlate WordPress database modifications to sort order fields with request source and authentication state
Deploy Web Application Firewall (WAF) rules that flag calls to WP Sort Order actions lacking a valid nonce parameter

Monitoring Recommendations

Enable request logging with authentication state so anonymous privileged actions are visible during review
Alert on burst activity against admin-ajax.php from a single IP address
Track plugin version inventory across all WordPress hosts to identify systems still running <= 1.3.5

How to Mitigate CVE-2026-28567

Immediate Actions Required

Update WP Sort Order to a version above 1.3.5 as soon as a patched release is available from the vendor
Deactivate and remove WP Sort Order on sites that do not require it until a fix is confirmed
Restrict access to /wp-admin/ and admin-ajax.php at the network or WAF layer where operationally feasible

Patch Information

Consult the Patchstack WP Sort Order Vulnerability advisory for the authoritative list of fixed versions and vendor guidance. No vendor patch URL is present in the NVD record at the time of publication.

Workarounds

Block unauthenticated requests to the plugin's AJAX actions using WAF rules that require a valid WordPress session cookie
Apply virtual patching at the reverse proxy to reject requests to the vulnerable endpoint
Limit administrative endpoints to trusted source IP ranges through .htaccess or Nginx allow/deny directives

bash

# Nginx example: restrict admin-ajax.php to authenticated cookie holders
location = /wp-admin/admin-ajax.php {
    if ($http_cookie !~* "wordpress_logged_in") {
        return 403;
    }
    include fastcgi_params;
    fastcgi_pass php_upstream;
}