CVE-2026-3367

What is known

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.

Business impact

Successful exploitation of CVE-2026-3367, a medium vulnerability (CVSS 4.4) affecting the affected product, may affect the confidentiality, integrity or availability of the vulnerable environment. The exact impact depends on the installed version, exposed interfaces and deployment configuration.

Recommended administrator action

Confirm whether the affected product is present and compare installed versions with the vendor advisory and NVD record. Apply the vendor patch or documented mitigation; until remediation is complete, reduce exposure of affected interfaces, review relevant logs and monitor for indicators of exploitation. DataHouse can support version verification, managed patching, network exposure reduction, log review and backup validation for dedicated, cloud and colocated environments.

Sources

• NVD
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