The Freemius SDK, as used by hundreds of WordPress plugin and theme developers, was vulnerable to Cross-Site Request Forgery and Information disclosure due to missing capability checks and nonce protection on the _get_debug_log, _get_db_option, and the _set_db_option functions in versions up to, and including 2.4.2. Any WordPress plugin or theme running a version of Freemius less than 2.4.3 is vulnerable.

The Modern Events Calendar plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 7.12.1 via the 'mec_fes_form' AJAX function. This makes it possible for authenticated attackers, with Subscriber-level access and above, to make web requests to arbitrary locations originating from the web application and can be used to query and modify information from internal services.

The Modern Events Calendar plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the set_featured_image function in all versions up to, and including, 7.11.0. This makes it possible for authenticated attackers, with subscriber access and above, to upload arbitrary files on the affected site's server which may make remote code execution possible. The plugin allows administrators (via its settings) to extend the ability to submit events to unauthenticated users, which would allow unauthenticated attackers to exploit this vulnerability.

The Modern Events Calendar lite plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Google API key and Calendar ID in versions up to, but not including, 7.1.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.

The Modern Events Calendar Lite WordPress plugin before 6.5.2 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup).

Cross-site scripting vulnerability in Modern Events Calendar Lite versions prior to 6.3.0 allows remote an authenticated attacker to inject an arbitrary script via unspecified vectors.

Authenticated (admin+ user) Stored Cross-Site Scripting (XSS) in Modern Events Calendar Lite (WordPress plugin) <= 6.5.1

The Modern Events Calendar Lite WordPress plugin before 6.4.0 does not sanitize and escape some of the Hourly Schedule parameters which could allow users with a role as low as contributor to perform Stored Cross-Site Scripting attacks

The Modern Events Calendar Lite WordPress plugin before 6.2.0 alloed any logged-in user, even a subscriber user, may add a category whose parameters are incorrectly escaped in the admin panel, leading to stored XSS.

The Modern Events Calendar Lite WordPress plugin before 6.1.5 does not sanitise and escape the time parameter before using it in a SQL statement in the mec_load_single_page AJAX action, available to unauthenticated users, leading to an unauthenticated SQL injection issue