ExpressVPN disclosed a vulnerability in its Windows desktop client that, under specific circumstances, could have permitted the leakage of user connection details.
The flaw was discovered by security researcher Adam-X through ExpressVPN’s bug bounty program and pertains to Remote Desktop Protocol (RDP) and other TCP traffic routed over port 3389.
Although the bug did not compromise encryption, it risked revealing the user’s true IP address and the fact of an RDP connection to on-network observers or internet service providers
https://gbhackers.com/expressvpn-windows-client-flaw/