The Checkout for PayPal plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'checkout_for_paypal' shortcode in all versions up to, and including, 1.0.32 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The Payments Plugin and Checkout Plugin for WooCommerce: Stripe, PayPal, Square, Authorize.net plugin for WordPress is vulnerable to Reflected Cross-Site Scripting due to the use of add_query_arg without appropriate escaping on the URL in all versions up to, and including, 1.112.0. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.

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 Checkout for PayPal WordPress plugin before 1.0.14 does not validate and escape some of its shortcode attributes before outputting them back in the page, which could allow users with a role as low as contributor to perform Stored Cross-Site Scripting attacks

plugin-fw/lib/yit-plugin-panel-wc.php in the YIT Plugin Framework through 3.3.8 for WordPress allows authenticated options changes.