Lockme OAuth2 calendars integration <= 2.11.0 - Authenticated (Administrator+) Stored Cross-Site Scripting via 'App ID' Setting
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.
Quick answer
Lockme calendars integration should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- *-2.11.0
Fixed versions
- 2.11.1
How to fix it
Lockme calendars integration is affected by CVE-2026-3367, a cross-site scripting issue in versions up to 2.11.0. Wordfence lists the official remediation as updating to version 2.11.1, or a newer patched version. Prioritize internet-facing WordPress sites, sites with public registration, customer portals, Elementor/page-builder surfaces, reservation or booking workflows, and admin workflows where the vulnerable feature is enabled. If immediate patching is not possible, disable the affected plugin or feature, restrict access, and monitor for exploitation until the update is installed.
- Inventory every WordPress site that has Lockme calendars integration installed, including production, staging, multisite, client, WooCommerce, marketplace, and booking environments.
- Confirm the installed Lockme calendars integration version and compare it with the affected range from the Wordfence advisory.
- Update Lockme calendars integration to version 2.11.1, or to a newer vendor-supported patched version from the official WordPress update channel.
- If the update cannot be applied immediately, disable Lockme calendars integration or the affected feature and restrict access with roles, authentication, WAF rules, or temporary route blocking.
- Review user-generated content, forms, widgets, saved plugin settings, comments, profiles, templates, page-builder output, and WooCommerce marketplace/vendor pages for injected scripts or unexpected HTML.
- Rotate administrator sessions, API keys, webhook secrets, payment or integration tokens, and affected credentials if logs or content review suggest compromise.
- Clear WordPress, object, CDN, page-builder, security plugin, WooCommerce, and browser caches after patching so vulnerable assets or stored payloads are not served.
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Verify the fix
- Confirm the running Lockme calendars integration version is version 2.11.1 or newer, and record the patched version in the remediation ticket.
- Verify the affected fields, widgets, forms, profile data, marketplace pages, or settings now sanitize input and escape output instead of rendering executable scripts.
- Review web server, WordPress, security plugin, WAF, database, WooCommerce, and application logs for exploitation attempts before and after the fix.
- Retest normal visitor, subscriber, customer, vendor, editor, administrator, checkout, form, API, booking, reservation, invoice, or integration workflows to confirm expected behavior still works.
- Run a fresh Fixnx scan and document the public exposure state, patched version, log review, and any cleanup evidence.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-3367?
Lockme calendars integration versions listed as affected should be reviewed: *-2.11.0.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.