ThirstyAffiliates < 3.10.5 - Subscriber+ unauthorized image upload + CSRF

The plugin lacks authorization checks in the ta_insert_external_image action, allowing a low-privilege user (with a role as low as Subscriber) to add an image from an external URL to an affiliate link. Further the plugin lacks csrf checks, allowing an attacker to trick a logged in user to perform the action by crafting a special request.

PoC

curl -b .cookies -d action=ta_insert_external_image -d url=‘https://THISISUSER.com/x.jpg’ -d link_id=5 ‘http://example.com/wp-admin/admin-ajax.php’