CVE-2026-39525: Booking Activities Auth Bypass Flaw

CVE-2026-39525 Overview

CVE-2026-39525 is a broken access control vulnerability in the Booking Activities WordPress plugin affecting versions up to and including 1.16.48.1. The flaw allows unauthenticated attackers to invoke functionality that should be restricted to authorized users. The issue is tracked under CWE-862: Missing Authorization. Network-based exploitation requires no privileges and no user interaction, making the plugin endpoints reachable directly by remote attackers. Successful exploitation can modify booking state and affect availability of the booking workflow on impacted sites.

Critical Impact
Unauthenticated attackers can reach protected plugin actions over the network, leading to limited integrity and availability impact on affected WordPress sites.

Affected Products

WordPress Booking Activities plugin versions <= 1.16.48.1
WordPress installations with the vulnerable plugin enabled
Sites exposing the plugin's AJAX or REST endpoints to unauthenticated traffic

Discovery Timeline

2026-06-15 - CVE-2026-39525 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2026-39525

Vulnerability Analysis

The Booking Activities plugin fails to enforce authorization checks on one or more action handlers. Endpoints that should validate the requester's capability or nonce instead process requests from any caller. An unauthenticated attacker sends crafted HTTP requests to the plugin's action handlers and triggers privileged operations. The defect aligns with CWE-862: Missing Authorization, where the application does not perform an authorization check when an actor attempts to access a resource or perform an action.

The EPSS score for this CVE is 0.242% as of 2026-06-18, indicating a low predicted probability of exploitation in the short term. No public proof-of-concept is referenced in the available data, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

Root Cause

The root cause is the absence of capability or nonce verification inside the plugin's request handlers. Functions that mutate booking-related state proceed without calling WordPress authorization primitives such as current_user_can() or check_ajax_referer(). Without these gates, the handlers treat anonymous traffic as legitimate requests.

Attack Vector

The attack vector is network-based. An attacker sends HTTP POST or GET requests to the plugin's admin-ajax.php action or REST route from any internet-connected host. No authentication, session, or social engineering is required. The impact is limited to partial integrity and availability degradation of booking data, consistent with the assigned CVSS metrics.

No verified exploit code is available in the referenced sources. Refer to the Patchstack Vulnerability Report for technical details on the affected handlers.

Detection Methods for CVE-2026-39525

Indicators of Compromise

Unauthenticated POST requests to /wp-admin/admin-ajax.php referencing Booking Activities actions
Unexpected modifications to booking records, schedules, or activity availability
Web server logs showing high-volume access to plugin endpoints from a single source IP

Detection Strategies

Inspect HTTP access logs for plugin action parameters originating from sessions without authentication cookies
Audit booking database tables for state changes that lack a corresponding authenticated user ID
Apply web application firewall rules that flag plugin action calls missing valid WordPress nonce tokens

Monitoring Recommendations

Forward WordPress and web server logs to a centralized logging platform for correlation
Alert on bursts of admin-ajax.php requests targeting Booking Activities actions from anonymous clients
Track plugin version inventory across hosted sites to identify instances still running 1.16.48.1 or earlier

How to Mitigate CVE-2026-39525

Immediate Actions Required

Update the Booking Activities plugin to a version newer than 1.16.48.1 once the vendor releases a fixed build
Restrict access to /wp-admin/admin-ajax.php plugin actions using a WAF or reverse proxy until patched
Review booking records for unauthorized changes since the plugin was installed

Patch Information

Consult the Patchstack Vulnerability Report for the latest patched version and vendor advisory details. Apply updates through the WordPress plugin manager or by replacing the plugin directory with the fixed release.

Workarounds

Disable the Booking Activities plugin on sites that cannot be updated immediately
Deploy WAF rules that require a valid authenticated session for requests to plugin AJAX actions
Limit network exposure of WordPress administrative endpoints to known IP ranges where feasible

bash

# Example WAF rule to block unauthenticated Booking Activities AJAX calls
# (adapt action names to match those identified in vendor advisory)
SecRule REQUEST_URI "@contains /wp-admin/admin-ajax.php" \
  "chain,deny,status:403,id:1039525,msg:'Block unauth Booking Activities action'"
SecRule ARGS:action "@rx ^bookacti_" \
  "chain"
SecRule &REQUEST_COOKIES:/wordpress_logged_in_/ "@eq 0"