Does an insecure router bypass the privacy guarantee of a VPN connection?
If you're talking about a VPN that extends to your PC/device, and similarly on the other side of the communications, and the insecure router somewhere in the path in between, then yes, an attacker should not be able to eavesdrop/snoop on the connection. The traffic would be encrypted and the attacker would not be able to understand it. This is one of the points of using the VPN in the first place. It creates a &quot;virtual&quot; private network over infrastructure (including routers) that may be insecure. If it doesn't even offer you this protection, then what is the point of using the VPN in the first place?
If you're talking about a site-to-site VPN, where traffic to/from your PC/device needs to get to/from the entry point of the VPN through, say, your office infrastructure, and if your office infrastructure is not otherwise secured, and this insecure router is part of that office infrastructure, then yes, an attacker may be able to eavesdrop/snoop, but even then it is not bypassing the privacy guarantee of the VPN, because the eavesdropping/snooping would be happening outside of the path that is protected by the VPN.