Related Issues

Summary

This is an internal request to update the Security Best Practices to point out a potential vulnerability in how IP addresses are exposed, and how to make exposure safer.

• K3S: Leaks all nodes public IPs within the TLS certificate SANs used for port 6443.

• RKE2: Leaks primary node public IP within the TLS certificate SANs used for port 6443. Leaks all nodes public IPs within the TLS certificate SANs used for port 9345 (supervisor).

If the supervisor and/or apiserver must be exposed, put them behind an external load-balancer with SSL offload enabled. Use of an external load-balancer is already documented as a requirement for provisioned k3s/rke2 clusters when using Authorized Cluster Endpoint.