CVE-2026-14216: Booking Calendar Plugin Auth Bypass Flaw

CVE-2026-14216 Overview

CVE-2026-14216 affects the Booking for Appointments and Events Calendar WordPress plugin in versions before 2.4.7. The plugin fails to require authentication before processing its pending notification queue. An unauthenticated attacker can trigger the dispatch of queued notifications and integration callbacks over the network. The weakness maps to [CWE-287] Improper Authentication and carries a network attack vector with low complexity and no privileges required.

Critical Impact
Unauthenticated attackers can force the WordPress site to dispatch queued notifications and invoke integration callbacks, causing message flooding and abuse of downstream integrations.

Affected Products

Booking for Appointments and Events Calendar WordPress plugin, versions prior to 2.4.7
WordPress installations with the vulnerable plugin activated
Third-party integrations that receive callbacks from the plugin queue

Discovery Timeline

2026-08-26 - CVE-2026-14216 published to NVD
2026-08-26 - Last updated in NVD database

Technical Details for CVE-2026-14216

Vulnerability Analysis

The plugin exposes an endpoint that processes the pending notification queue without validating the caller's identity. An unauthenticated request can advance the queue and cause the plugin to send outbound notifications and invoke registered integration callbacks. This allows attackers to abuse the queue to flood recipients with duplicated messages, replay pending events, and trigger third-party webhooks at attacker-chosen times. The impact scope covers integrity of notification state and availability of the messaging pipeline, without direct disclosure of sensitive data.

Root Cause

The queue-processing handler lacks an authentication check and does not verify a WordPress nonce or capability. The plugin treats queue processing as a background task but exposes it to any network caller that can reach the WordPress site. Missing authorization on state-changing functionality is a classic [CWE-287] Improper Authentication defect.

Attack Vector

An attacker sends an HTTP request to the plugin endpoint that triggers queue dispatch. No credentials, session, or user interaction are required. Repeated invocations amplify impact by re-dispatching notifications and calling registered integration URLs. See the WPScan Vulnerability Report for technical details on the affected endpoint.

Detection Methods for CVE-2026-14216

Indicators of Compromise

Unauthenticated HTTP requests to the plugin's queue-processing endpoint from unknown source IPs
Bursts of outbound notification emails or webhook calls not correlated with legitimate booking activity
Duplicate delivery of the same booking notification to end users or integrations
Spikes in wp-admin/admin-ajax.php or plugin-specific action calls without an authenticated session cookie

Detection Strategies

Monitor web server access logs for anonymous POST or GET requests targeting the plugin's notification action parameters.
Correlate outbound SMTP and webhook traffic with authenticated booking events to surface unauthorized dispatch.
Alert on repeated calls from a single source IP to the plugin endpoint over short time windows.

Monitoring Recommendations

Enable verbose logging on the WordPress reverse proxy or web application firewall for plugin routes.
Track notification-queue length and dispatch counts as operational metrics and alert on anomalies.
Review integration platform logs for callbacks received outside normal booking workflows.

How to Mitigate CVE-2026-14216

Immediate Actions Required

Update the Booking for Appointments and Events Calendar plugin to version 2.4.7 or later.
Audit recent notification and webhook activity for evidence of unauthorized dispatch.
Rotate any integration secrets or webhook tokens exposed through the callback endpoints.

Patch Information

The vendor addressed the issue in version 2.4.7 by requiring authentication before processing the pending notification queue. Administrators should apply the update through the WordPress plugin dashboard or by replacing the plugin files with the fixed release. Refer to the WPScan Vulnerability Report for advisory details.

Workarounds

Restrict access to the plugin's queue-processing endpoint at the web application firewall until the patch is applied.
Deactivate the plugin on production sites that cannot be updated immediately.
Enforce authentication on admin-ajax.php actions related to the plugin using server-level access rules.

bash

# Example WAF rule to block unauthenticated queue processing until patched
# Adjust the action parameter to match the plugin's specific handler name
SecRule REQUEST_URI "@contains admin-ajax.php" \
  "chain,deny,status:403,id:1026142160,msg:'Block unauthenticated booking plugin queue dispatch'"
  SecRule ARGS:action "@rx (process_notification_queue|dispatch_pending)" \
    "chain"
    SecRule &REQUEST_COOKIES:/wordpress_logged_in_/ "@eq 0"