The Travelpayouts: All Travel Brands in One Place WordPress plugin through 1.1.15 is vulnerable to Open Redirect due to insufficient validation on the travelpayouts_redirect variable. This makes it possible for unauthenticated attackers to redirect users to potentially malicious sites if they can successfully trick them into performing an action.
https://wpscan.com/vulnerability/2f17a274-8676-4f4e-989f-436030527890/