CVE-2024-11270: WebinarPress RCE Vulnerability

CVE-2024-11270 Overview

CVE-2024-11270 affects the WordPress Webinar Plugin – WebinarPress, a plugin used to run webinars on WordPress sites. The vulnerability stems from a missing capability check on the sync-import-imgs function combined with missing file type validation. Authenticated attackers with subscriber-level access or higher can create arbitrary files on the server. This file creation primitive can be leveraged to achieve remote code execution on affected WordPress installations. All plugin versions up to and including 1.33.24 are affected. The issue is tracked as [CWE-862] Missing Authorization.

Critical Impact
Authenticated attackers with subscriber-level access can write arbitrary files to the WordPress server, enabling remote code execution and full site compromise.

Affected Products

WebinarPress plugin for WordPress, all versions up to and including 1.33.24
WordPress sites permitting subscriber-level registration with WebinarPress installed
Deployments referencing includes/class-webinarsysteem-ajax.php prior to changeset 3216237

Discovery Timeline

2025-01-08 - CVE-2024-11270 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-11270

Vulnerability Analysis

The vulnerability resides in the sync-import-imgs AJAX handler exposed by WebinarPress. The handler is designed to import image assets but does not enforce a capability check to restrict which authenticated roles may invoke it. As a result, any logged-in user, including low-privilege subscribers, can call the endpoint.

Beyond the missing authorization, the handler does not validate the type or extension of the file it writes to disk. An attacker can supply a URL or payload that resolves to a PHP file or other executable content. The plugin then writes that content into a location served by the web server.

Once the attacker-controlled file lands within the WordPress webroot, requesting it causes the PHP interpreter to execute the payload. This turns a file-creation weakness into remote code execution under the web server's user context. The Wordfence advisory documents both the missing capability check and the absence of file type validation as the root causes.

Root Cause

The root cause is [CWE-862] Missing Authorization. The sync-import-imgs function in class-webinarsysteem-ajax.php fails to verify the caller's WordPress capabilities before performing a privileged file operation. Compounding this, the code does not restrict file extensions or MIME types, so arbitrary content, including PHP source, can be written to disk.

Attack Vector

Exploitation is remote and requires authentication at the subscriber level or higher. On WordPress sites that allow open user registration, this bar is trivial to clear. The attacker sends a crafted request to the vulnerable AJAX action, causing the server to fetch and store a malicious file. The attacker then requests the newly created file to trigger code execution.

See the Wordfence Vulnerability Report and the WordPress Changeset Update for the specific handler modifications that address the flaw.

Detection Methods for CVE-2024-11270

Indicators of Compromise

Unexpected PHP or executable files appearing under WebinarPress upload or import directories inside wp-content
POST requests to admin-ajax.php invoking the sync-import-imgs action from subscriber accounts
Outbound HTTP fetches initiated by the WordPress host to attacker-controlled URLs referenced in import parameters
New or recently modified files in the webroot with owner matching the PHP-FPM or web server user

Detection Strategies

Alert on AJAX calls to the sync-import-imgs action originating from non-administrative user sessions
Monitor filesystem changes within wp-content/plugins/wp-webinarsystem/ and any WebinarPress-managed upload paths
Correlate new user registrations followed shortly by AJAX activity and outbound network requests from the web server
Inspect WordPress access logs for HTTP requests to unfamiliar .php files created after plugin activity

Monitoring Recommendations

Enable WordPress audit logging to capture AJAX action names, user IDs, and request parameters
Track EPSS scoring changes for CVE-2024-11270 as exploit tooling evolves; current EPSS is 0.91%
Route web server and PHP error logs to a centralized platform for correlation with authentication events
Review scheduled tasks and cron entries created after suspected exploitation attempts

How to Mitigate CVE-2024-11270

Immediate Actions Required

Update the WebinarPress plugin to a version later than 1.33.24 that incorporates changeset 3216237
Disable open user registration or restrict the default role to prevent unauthenticated attackers from obtaining subscriber accounts
Audit existing users for unexpected subscriber-level accounts created before patching
Scan the webroot for unauthorized PHP files and remove any confirmed webshells

Patch Information

The vendor addressed the issue in the WebinarPress source tree via WordPress changeset 3216237, which modifies includes/class-webinarsysteem-ajax.php to add proper capability enforcement and file handling logic. Site operators should upgrade to the fixed release through the WordPress plugin updater.

Workarounds

Deactivate and remove the WebinarPress plugin until an upgrade can be applied
Block requests to admin-ajax.php where the action parameter equals sync-import-imgs at the web application firewall
Disable PHP execution within WordPress upload directories using web server configuration
Restrict WordPress user registration to trusted email domains or require administrator approval

bash

# Example nginx configuration to block PHP execution in WordPress uploads
location ~* /wp-content/uploads/.*\.php$ {
    deny all;
    return 403;
}

# Example WAF rule pattern to block the vulnerable AJAX action
# ModSecurity example
SecRule REQUEST_URI "@contains /wp-admin/admin-ajax.php" \
    "chain,deny,status:403,id:1102024,msg:'Block WebinarPress sync-import-imgs CVE-2024-11270'"
SecRule ARGS:action "@streq sync-import-imgs"