CVE-2026-3367: Lustmored Lockme Calendars Integration

Medium severity, CVSS 4.4. EPSS: 0.4% chance of exploitation in the next 30 days.

The Lockme OAuth2 calendars integration plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'App ID' setting in all versions up to, and including, 2.11.0. This is due to insufficient input sanitization and output escaping. The register_setting() call on line 197 lacks a sanitize callback, allowing unsanitized data to be stored via update_option(). When the settings page is rendered, the stored value is echoed directly into an HTML input's value attribute without esc_attr() on line 212. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary web scripts in the settings page that will execute whenever a user accesses the plugin settings page. Multiple fields are affected: App ID (client_id), App Secret (client_secret), Bookings ID prefix (id_prefix), and API domain (api_domain). This vulnerability is particularly impactful in WordPress multisite installations where administrators of individual sites should not be able to execute JavaScript affecting other users.

Affected products

• Lustmored Lockme Calendars Integration: up to and including 2.11.0

Published 2026-07-11. Last modified 2026-07-13.