The Contest Gallery – Upload & Vote Photos, Media, Sell with PayPal & Stripe plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 30.0.2 via the RegistryUserRole parameter. This is due to the plugin's admin menu being registered at the editposts capability level — granting Contributor-level users access to the plugin's admin pages and a valid cgadmin nonce — while the option-saving handler in change-options-and-sizes.php performs no currentusercan() capability check beyond checkadminreferer('cgadmin'), and the RegistryUserRole value is processed only through sanitizetextfield() and htmlentities() without restriction to an allowlist of permitted role names. This makes it possible for authenticated attackers, with author-level access and above, to overwrite the plugin's stored RegistryUserRole option with administrator, which the cgcreatewpuserfromgoogleuser function then reads back from the contestgal1eryregistryandloginoptions database table without any allowlist validation and passes directly to wpupdateuser(), effectively promoting a newly registered Google sign-in account to Administrator.

The Contest Gallery plugin for WordPress is vulnerable to an authentication bypass leading to admin account takeover in all versions up to, and including, 28.1.5. This is due to the email confirmation handler in users-registry-check-after-email-or-pin-confirmation.php using the user's email string in a WHERE ID = %s clause instead of the numeric user ID, combined with an unauthenticated key-based login endpoint in ajax-functions-frontend.php. When the non-default RegMailOptional=1 setting is enabled, an attacker can register with a crafted email starting with the target user ID (e.g., 1poc@example.test), trigger the confirmation flow to overwrite the admin's useractivationkey via MySQL integer coercion, and then use the postcg1lloginuserbykey AJAX action to authenticate as the admin without any credentials. This makes it possible for unauthenticated attackers to take over any WordPress administrator account and gain full site control.