CVE-2026-82607: Profile Builder Plugin RCE Vulnerability

CVE-2026-82607 Overview

CVE-2026-82607 is an unrestricted file upload vulnerability in the Cozmoslabs Profile Builder plugin for WordPress through version 3.16.1. The flaw resides in the wppb_ajax_simple_avatar function within the Avatar Simple Upload AJAX Handler exposed via /wp-admin/admin-ajax.php. Remote attackers can manipulate the handler to upload arbitrary files without proper authentication or file-type enforcement. Public exploit details have been released, increasing the risk of opportunistic abuse against affected WordPress sites. The vendor addressed the issue in Profile Builder version 3.16.2.

Critical Impact
Unauthenticated remote attackers can upload arbitrary media files to vulnerable WordPress sites, enabling content abuse and potential follow-on exploitation.

Affected Products

Cozmoslabs Profile Builder Plugin for WordPress versions up to and including 3.16.1
Component: Avatar Simple Upload AJAX Handler (wppb_ajax_simple_avatar)
Endpoint: /wp-admin/admin-ajax.php

Discovery Timeline

2026-08-31 - CVE-2026-82607 published to NVD
2026-08-31 - Last updated in NVD database

Technical Details for CVE-2026-82607

Vulnerability Analysis

The vulnerability is categorized under [CWE-284: Improper Access Control]. The Profile Builder plugin registers the wppb_ajax_simple_avatar AJAX action to accept avatar image uploads. The handler fails to properly restrict who may invoke it and does not sufficiently validate the uploaded content. As a result, remote actors can submit crafted upload requests to /wp-admin/admin-ajax.php and place files on the server. Because the endpoint is reachable over the network without prior authentication, exploitation requires only HTTP access to the target WordPress installation.

Root Cause

The root cause is missing or insufficient access control on the avatar upload AJAX action. The handler treats client-side checks as authoritative and does not enforce server-side authorization or strict file validation before writing the uploaded object to disk. Additional analysis is available in the Cipher Security Labs research article.

Attack Vector

An attacker sends an HTTP POST request to /wp-admin/admin-ajax.php with the action parameter set to the vulnerable AJAX hook and a file payload in the request body. The server processes the request through wppb_ajax_simple_avatar and stores the resulting file within the WordPress uploads directory. No user interaction or authenticated session is required.

Refer to the VulDB entry for CVE-2026-82607 and the Cipher Security Labs write-up for technical exploitation details. No verified proof-of-concept code is reproduced here.

Detection Methods for CVE-2026-82607

Indicators of Compromise

Unexpected POST requests to /wp-admin/admin-ajax.php containing action=wppb_ajax_simple_avatar from unauthenticated sessions
New or unfamiliar files appearing in the WordPress wp-content/uploads/ directory, particularly avatar-related subdirectories
Files with mismatched extensions or MIME types uploaded through the avatar handler

Detection Strategies

Inspect web server access logs for repeated calls to admin-ajax.php with the wppb_ajax_simple_avatar action originating from external IP addresses
Correlate upload events with the absence of an authenticated user session cookie in the same request
Hash and baseline files in the uploads directory to identify anomalous additions

Monitoring Recommendations

Enable WordPress audit logging that captures AJAX action invocations and file upload events
Forward web server and application logs to a centralized analytics platform for retention and query
Alert on newly created executable or script files within wp-content/uploads/

How to Mitigate CVE-2026-82607

Immediate Actions Required

Upgrade Cozmoslabs Profile Builder to version 3.16.2 or later on every WordPress instance where the plugin is installed
Audit the wp-content/uploads/ directory for unauthorized files created since the plugin was deployed
Review web server logs for prior requests to wppb_ajax_simple_avatar and investigate any suspicious uploads

Patch Information

Cozmoslabs released Profile Builder version 3.16.2, which resolves the unrestricted upload issue. Version details are documented in the Cozmos Labs Profile Builder Changelog. Administrators should apply the update through the WordPress plugin manager or by replacing plugin files with the patched release.

Workarounds

If patching is temporarily infeasible, deactivate the Profile Builder plugin until the upgrade can be applied
Restrict access to /wp-admin/admin-ajax.php for the wppb_ajax_simple_avatar action at the web application firewall (WAF) or reverse proxy layer
Configure the web server to deny execution of PHP and other server-side scripts within the wp-content/uploads/ directory

bash

# Example Apache directive to block script execution in the uploads directory
<Directory "/var/www/html/wp-content/uploads">
    php_flag engine off
    <FilesMatch "\.(php|phtml|phar|pl|py|jsp|asp|sh|cgi)$">
        Require all denied
    </FilesMatch>
</Directory>