CVE-2026-16546: WordPress Volunteer Management Auth Bypass

CVE-2026-16546 Overview

CVE-2026-16546 affects the Wired Impact Volunteer Management WordPress plugin in versions before 2.8.2. The plugin exposes an AJAX action that does not perform authorization checks or verify RSVP ownership. Any authenticated user with a role as low as Subscriber can remove arbitrary users' RSVPs from any volunteer opportunity. The flaw is categorized under [CWE-862] Missing Authorization.

Critical Impact
Low-privileged Subscriber accounts can delete other users' volunteer RSVPs, corrupting event data and disrupting volunteer coordination for organizations relying on the plugin.

Affected Products

Wired Impact Volunteer Management WordPress plugin versions prior to 2.8.2
WordPress sites running Subscriber-level or higher user registration
Volunteer organization websites that rely on this plugin for RSVP tracking

Discovery Timeline

2026-08-04 - CVE-2026-16546 published to NVD
2026-08-04 - Last updated in NVD database

Technical Details for CVE-2026-16546

Vulnerability Analysis

The vulnerability resides in an AJAX handler that removes RSVPs from volunteer opportunities. The handler fails to perform two required checks. First, it does not enforce capability-based authorization on the calling user. Second, it does not verify that the RSVP being deleted actually belongs to the authenticated user submitting the request.

Because WordPress AJAX endpoints registered via wp_ajax_{action} are accessible to any logged-in user, the absence of role or ownership validation allows Subscriber accounts to invoke the delete action. Attackers can iterate through RSVP identifiers and remove records belonging to any volunteer.

The impact is limited to integrity of RSVP data. Confidentiality and availability of the broader system are not directly affected, though the corruption of scheduling data may cause downstream operational disruption for volunteer coordinators.

Root Cause

The root cause is a Missing Authorization defect [CWE-862]. The AJAX action lacks a current_user_can() capability check and does not compare the RSVP owner identifier against the current user ID before executing the deletion query.

Attack Vector

An attacker registers or logs in as a Subscriber on the target WordPress site. The attacker then issues a crafted admin-ajax.php POST request referencing an RSVP identifier belonging to another user. The vulnerable handler processes the request and deletes the record without validation.

The vulnerability manifests in the plugin's RSVP removal AJAX handler. See the WPScan Vulnerability Report for technical details.

// No verified proof-of-concept code is publicly available.
// The vulnerability is triggered via an authenticated POST to
// wp-admin/admin-ajax.php targeting the plugin's RSVP removal action
// with an arbitrary RSVP identifier.

Detection Methods for CVE-2026-16546

Indicators of Compromise

Unexpected deletions of RSVP records in the plugin's database tables not correlated with the record owner's session
admin-ajax.php POST requests from low-privilege accounts referencing the plugin's RSVP removal action
Volunteer coordinators reporting missing signups for users who did not cancel

Detection Strategies

Review web server access logs for repeated POST requests to wp-admin/admin-ajax.php originating from Subscriber accounts
Enable WordPress database query logging to correlate DELETE statements against RSVP tables with the acting user ID
Compare RSVP audit trails against user session records to identify ownership mismatches

Monitoring Recommendations

Alert on unusual volumes of AJAX requests from newly registered Subscriber accounts
Monitor for enumeration patterns targeting sequential RSVP identifiers
Track database write operations against plugin tables and flag activity from non-administrative roles

How to Mitigate CVE-2026-16546

Immediate Actions Required

Update the Wired Impact Volunteer Management plugin to version 2.8.2 or later
Audit the WordPress user list and remove unknown Subscriber accounts
Review RSVP records for unauthorized deletions and restore from backups where necessary

Patch Information

The vendor addressed the issue in Wired Impact Volunteer Management version 2.8.2 by adding authorization and ownership checks to the affected AJAX action. Site administrators should apply the update through the WordPress plugin manager. Additional detail is available in the WPScan Vulnerability Report.

Workarounds

Disable open user registration to prevent attackers from obtaining Subscriber accounts
Deactivate the plugin until the patched version can be deployed
Restrict access to wp-admin/admin-ajax.php at the web application firewall for the vulnerable action name

bash

# Update the plugin via WP-CLI
wp plugin update wired-impact-volunteer-management --version=2.8.2

# Verify the installed version
wp plugin get wired-impact-volunteer-management --field=version