Chatify before 1.6.4 Pusher Authorization Bypass via /chat/auth Endpoint

Chatify before 1.6.4 contains an authorization bypass vulnerability in the Pusher channel authorization endpoint that allows authenticated users to subscribe to other users' private channels by supplying arbitrary channel names. Attackers can request a signature for private-chatify.<victim id> via POST /chat/auth to receive the victim's incoming private messages and attachments in real time.