diff --git a/plugins/commands/serve/mappers/internal/graph/vertex.rb b/plugins/commands/serve/mappers/internal/graph/vertex.rb
index <HASH>..<HASH> 100644
--- a/plugins/commands/serve/mappers/internal/graph/vertex.rb
+++ b/plugins/commands/serve/mappers/internal/graph/vertex.rb
@@ -48,6 +48,7 @@ module VagrantPlugins
             # @param [Vertex]
             # @return [Boolean]
             def ==(v)
+              return false if !v.respond_to?(:hash_code)
               v.hash_code == hash_code
             end
             alias_method :eql?, :==
Return false if RHS does not implement hash_code