Hustle <= 7.8.14.3 - Missing Authorization to Authenticated (Custom+) ESP Credential Overwrite and Irreversible OAuth Token Deletion via 'hustle_provider_migrate_hubspot' (and sibling migrate_*) AJAX Action

The Hustle – Email Marketing, Lead Generation, Optins, Popups plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 7.8.14.3. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for authenticated attackers, with custom-level access and above, to overwrite the site's active ESP integration credentials (AWeber, Constant Contact, Infusionsoft, ConvertKit, or HubSpot API keys) with attacker-controlled values — diverting all subsequent Hustle form lead submissions to the attacker's ESP tenant — and, for HubSpot, irreversibly delete the operator's OAuth token, OAuth referer, and OAuth current-page option rows. This requires the attacker to hold the plugin-granted hustle_create capability (e.g., an Editor delegated hustle_create but not hustle_edit_integrations via Hustle's Permissions tab), which allows them to load a Hustle module wizard page and obtain the hustle_provider_action nonce needed to reach the vulnerable handlers.