The Modern Events Calendar Lite WordPress plugin before 6.1.5 does not sanitise and escape the current_month_divider parameter of its mec_list_load_more AJAX call (available to both unauthenticated and authenticated users) before outputting it back in the response, leading to a Reflected Cross-Site Scripting issue

The Modern Events Calendar Lite WordPress plugin before 5.22.3 does not properly sanitize or escape values set by users with access to adjust settings withing wp-admin.

The Modern Events Calendar Lite WordPress plugin before 5.22.2 does not escape some of its settings before outputting them in attributes, allowing high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed.

Lack of authorisation checks in the Modern Events Calendar Lite WordPress plugin, versions before 5.16.5, did not properly restrict access to the export files, allowing unauthenticated users to exports all events data in CSV or XML format for example.

Unvalidated input and lack of output encoding in the Modern Events Calendar Lite WordPress plugin, versions before 5.16.5, did not sanitise the mic_comment field (Notes on time) when adding/editing an event, allowing users with privilege as low as author to add events with a Cross-Site Scripting payload in them, which will be triggered in the frontend when viewing the event.

Arbitrary file upload in the Modern Events Calendar Lite WordPress plugin, versions before 5.16.5, did not properly check the imported file, allowing PHP ones to be uploaded by administrator by using the 'text/csv' content-type in the request.

Unvalidated input in the Modern Events Calendar Lite WordPress plugin, versions before 5.16.6, did not sanitise the mec[post_id] POST parameter in the mec_fes_form AJAX action when logged in as an author+, leading to an authenticated SQL Injection issue.

Multiple Stored Cross-site scripting (XSS) vulnerabilities in the Webnus Modern Events Calendar Lite plugin through 5.1.6 for WordPress allows remote authenticated users (with minimal permissions) to inject arbitrary JavaScript, HTML, or CSS via Ajax actions. This affects mec_save_notifications and import_settings.