What the vulnerability does
Description
K2 ≤ 2.24 contains a mass-assignment defect in the K2 system user plugin `plg_user_k2`. A Registered Joomla user, by including the field `K2UserForm=1` in a standard `com_users` `profile.save` POST, can write arbitrary values into the `notes`, `image`, and `plugins` columns of their own row in the `#__k2_users` table — none of which are exposed by the K2 frontend profile-edit form.
