The Post Grid Gutenberg Blocks and WordPress Blog Plugin – PostX plugin for WordPress is vulnerable to unauthorized plugin installation/activation due to a missing capability check on the 'install_required_plugin_callback' function in all versions up to, and including, 4.1.16. This makes it possible for authenticated attackers, with Subscriber-level access and above, to install and activate arbitrary plugins which can be leveraged to achieve remote code execution if another vulnerable plugin is installed and activated.

The Post Grid Gutenberg Blocks and WordPress Blog Plugin – PostX plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the 'postx_presets_callback' function in all versions up to, and including, 4.1.2. This makes it possible for authenticated attackers, with Contributor-level access and above, to change arbitrary options on affected sites. This can be used to enable new user registration and set the default role for new users to Administrator.

The Post Grid Gutenberg Blocks and WordPress Blog Plugin – PostX plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's file uploading feature in all versions up to, and including, 4.1.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.