Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Starting in version 1.14.0 and prior to versions 1.14.8 and 1.15.2, In Cilium clusters with WireGuard enabled and traffic matching Layer 7 policies Wireguard-eligible traffic that is sent between a node's Envoy proxy and pods on other nodes is sent unencrypted and Wireguard-eligible traffic that is sent between a node's DNS proxy and pods on other nodes is sent unencrypted. This issue has been resolved in Cilium 1.14.8 and 1.15.2 in in native routing mode (`routingMode=native`) and in Cilium 1.14.4 in tunneling mode (`routingMode=tunnel`). Not that in tunneling mode, `encryption.wireguard.encapsulate` must be set to `true`. There is no known workaround for this issue.
Vulmon