Apparently there are reports of it also affecting RSWCS to some extent too. However,
I believe that all servers are affected by this problem, however due to the open nature of the information of connected primaries in WCS and RSWCS it highlights this issue more. If the network is being flooded by fake primaries then it will not affect a particular server type. But if servers are connecting and disconnecting from bad primaries over and over in the background, and not displaying any errors then people will assume its actually not affected.
edit: also note, this will affect all primary and secondary clients and caches too, (it never does affect a single point) but im happy to explain this if it helps anyone.