on GCP we are using an internet facing TCP Load Balancer in front of our Kubernetes cluster where our application runs. The TCP Load Balancer is configured to forward ports 80 and 443, TCP obviously.
Our security department recently ran a vulnerability scan on our application and apparently detected that UDP port 1900 is open on the Load Balancer IP address. I'm positive that our application behind the Load Balancer does not listen on UDP port 1900, or any UDP port.
Has anybody seen such open UDP ports on internet facing GCP TCP Load Balancers? Is there a reason or explanation for it? Unfortunately I was not able to find any documentation or discussion about this yet and it leaves me quite puzzled. I'd be thankful for any advice.