CVE-2025-54676: Vcita Calendar Stored XSS Vulnerability

CVE-2025-54676 Overview

CVE-2025-54676 is a stored cross-site scripting (XSS) vulnerability in the vcita Online Booking & Scheduling Calendar plugin for WordPress. The flaw affects all plugin versions up to and including 4.5.3. Attackers with low-privileged authenticated access can inject persistent JavaScript payloads that execute in the browsers of other users, including administrators. The issue is tracked under [CWE-79] (Improper Neutralization of Input During Web Page Generation).

Critical Impact
Authenticated attackers can store malicious scripts that execute in visitors' and administrators' browsers, enabling session theft, account takeover, and unauthorized actions within the WordPress dashboard.

Affected Products

vcita Online Booking & Scheduling Calendar for WordPress (meeting-scheduler-by-vcita)
All versions from initial release through 4.5.3
WordPress installations running the plugin with the default configuration

Discovery Timeline

2025-08-14 - CVE-2025-54676 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-54676

Vulnerability Analysis

The plugin fails to properly neutralize user-supplied input before rendering it inside web pages generated by the booking and scheduling interface. This allows an authenticated user to submit input containing HTML or JavaScript that the server stores and later renders unescaped. When another user loads the affected page, the browser interprets the payload as executable script within the site's origin.

Stored XSS is more severe than reflected variants because the payload persists in the application database. Each visitor to the affected view triggers execution automatically, without requiring a crafted link or user interaction beyond normal browsing. In WordPress environments, this often escalates to full site compromise when an administrator triggers the payload.

Root Cause

The root cause is missing output encoding and insufficient input sanitization in plugin components that render user-controlled data. The plugin does not apply WordPress escaping helpers such as esc_html(), esc_attr(), or wp_kses() when writing stored values back into the DOM.

Attack Vector

Exploitation requires network access to the WordPress site and low-privileged authentication. The attacker submits a payload through an input field processed by the vulnerable plugin. A separate user must load the affected page for the script to execute, satisfying the user interaction requirement. The scope change reflects the ability of injected script to affect a browser security context different from the vulnerable component.

Refer to the Patchstack XSS Vulnerability Report for additional technical context.

Detection Methods for CVE-2025-54676

Indicators of Compromise

Unexpected <script>, <iframe>, or event-handler attributes (e.g., onerror, onload) stored in plugin-related database tables
Outbound requests from administrator browsers to unfamiliar domains after visiting booking or scheduling pages
New WordPress administrator accounts created shortly after plugin pages were viewed
Modifications to wp_options, theme files, or plugin files without a corresponding administrative action

Detection Strategies

Audit stored plugin data for HTML tags or JavaScript syntax using database queries against fields populated by meeting-scheduler-by-vcita
Deploy a web application firewall rule set to flag XSS payload patterns in requests targeting plugin endpoints
Enable Content Security Policy (CSP) reporting to identify inline script execution originating from booking pages

Monitoring Recommendations

Log and review all POST requests to plugin admin-ajax endpoints and REST routes
Alert on WordPress user role changes, plugin installations, and file modifications correlated with plugin page access
Correlate browser telemetry from administrator workstations with WordPress access logs to identify script-triggered activity

How to Mitigate CVE-2025-54676

Immediate Actions Required

Update the Online Booking & Scheduling Calendar plugin to a version later than 4.5.3 as soon as the vendor publishes a fix
Restrict who can submit content processed by the plugin by tightening WordPress role assignments
Review existing plugin-stored records for injected script content and remove any malicious entries
Rotate credentials and session tokens for any administrator that accessed affected pages during the exposure window

Patch Information

At the time of NVD publication, the advisory indicates the issue affects all versions through 4.5.3. Consult the Patchstack advisory and the plugin's WordPress.org listing for the current fixed release before upgrading.

Workarounds

Deactivate the meeting-scheduler-by-vcita plugin until a patched release is confirmed
Deploy a WAF rule blocking HTML and script characters in requests to plugin endpoints
Enforce a strict Content Security Policy that disallows inline scripts and untrusted script sources
Limit plugin submission capabilities to trusted authenticated users only

bash

# Example: deactivate the vulnerable plugin using WP-CLI
wp plugin deactivate meeting-scheduler-by-vcita

# Verify the plugin status
wp plugin status meeting-scheduler-by-vcita